Wikipedia:Peer review/Thorium/archive1

Thorium

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This peer review discussion has been closed.

I've listed this article for peer review because I'd like to take it to FA. I worked on it two years ago to GA-level and I would like to know what is still needed.

Thanks, Double sharp (talk) 04:53, 25 June 2016 (UTC)[reply]

Comments by Dunkleosteus77

Comments below   User:Dunkleosteus77 |push to talk  18:00, 30 June 2016 (UTC):[reply]

• • Now that I added refs 27 and 28, I edited all the numbers below to make it clearer for myself Double sharp (talk) 11:13, 3 July 2016 (UTC)[reply]
• I find ref no. 102 unreliable (The Straight Dope)
• Use this convert to convert ISBN-10 to ISBN-13 as per WP:ISBN
• not properly cited (most need an access date):
  • 1
  • 25
  • 29
  • 30
  • 75
  • 40
  • 56
  • 61
  • 70
  • 75
  • 85
  • 89
• journals don't need access dates (like ref no. 47)
• websites need access dates
• ref no. 39 has a cite error
  •  Done Fixed Double sharp (talk) 11:22, 3 July 2016 (UTC)[reply]
• add |language=German parameter to ref no. 54
  •  Done Fixed (and also noted that 52 is in French and 53 also in German) Double sharp (talk) 11:22, 3 July 2016 (UTC)[reply]
• add |language=German parameter to ref no. 111
  •  Done Fixed Double sharp (talk) 11:22, 3 July 2016 (UTC)[reply]
• ref no. 56 is not properly cited
  • Found a better ref for this Double sharp (talk) 11:24, 3 July 2016 (UTC)[reply]
• deadlinks:
  • 14
  • 24
  • 29
  • 111
    •  Done Fixed 29 and 111. 15 and 24 still work, but have disappeared behind a "registration wall". Double sharp (talk) 11:22, 3 July 2016 (UTC)[reply]
• duplinks:
  • uranium (in the lead and three times in the prose)
  • plutonium (twice)
  • electron configuration (twice)
  • coordination number (twice)
  • mass number
  • electronvolt
  • steel
  • Jöns Jakob Berzelius
  • cerium
  • oxidation state
  • lanthanide (twice)
  • protactinium
  • uranium-235
  • neptunium
  • uranium-238
  • uranium-233
  • tin
  • hafnium
  • scandium
  • yttrium (twice)
  • monazite
  • nitric acid (twice)
  • rare-earth element (twice)
  • pH
  • hydrochloric acid
  • gas mantle (three times)
  • hydroxide
  • electrolysis
  • Thorium tetrafluoride
  • isotypic
  • hygroscopic
  • monoclinic
  • alkali metals
  • ammonium
  • sulfer
  • nitrogen
  • phosphorus
  • arsenic
  • bismuth
  • hydrogen (twice)
  • oxygen
  • carbon (twice)
  • nitrate
  • carbonate
  • phosphate (twice)
  • neutron capture
  • uranium dioxide
  • transuranic element
  • ionium-thorium dating
  • age of the earth
  • tungsten
  • electron
  • cerium dioxide
  • alpha particle
  • pyrophoric
  • radon (twice)
  • radium
  • actinium
    •  Done Double sharp (talk) 06:39, 2 July 2016 (UTC)[reply]

Tip: to highlight duplicate links, you can install a script (which actually means copying a small amount of text to a Wiki page), see

• Use this converter to convert ISBN-10 to ISBN-13 (as per WP:ISBN)
• ref no. 117 has a bracket after the access-date
• remove the url for ref no. 72
• ref no. 111 seems unreliable (The Straight Dope)

Review by R8R

I'll review the article.--

• Why is periodic table location covered here? Atomic seems to be a better place
  • Well, mostly because for chemical elements, location is destiny. I confess I am unhappy about the structure with "chemical" so far from "compounds", but I can stomach it by interpreting "characteristics" as being a guide to Th the metal, while "compounds" to be a guide of what Th-containing compounds are like.
    • I've had the idea. I brushed it away by thinking the whole article is a key to the element. Besides, I don't have my books at the moment, but I think G&E or Ullmann also separate physical properties from chemical ones.--
      talk) 21:20, 3 July 2016 (UTC)[reply
      ]
  • I had an idea (now implemented) of removing all the subheaders in this and making the order physical-atomic-chemistry. Isotopes is so huge that it might as well be a new section. Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]

• I think all metals "can be cold-rolled, swaged, and drawn"
  • True. (Well, I guess not mercury.) So I have now added that this is entirely normal for all metals. (I suppose it makes sense to say because in my experience people tend to think of thorium and uranium as somehow different due to their radioactivity. They're really not. You can work with them just as you would with any other metal; it's just not a good idea for your health. There are no physical barriers that stop you, though.) Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]
    • I was still surprised after I saw you had that "can be cold-rolled, swaged, and drawn" and read your "True," but if some people actually think of Th and U as different from most other metals, than sure, the phrase can stay.--
      talk) 21:20, 3 July 2016 (UTC)[reply
      ]
      • Never underestimate
        tritium watch... ^_^ Did you know that you can buy thorium rings quite legally? It would be such a fun way to mess with people, but it wouldn't be very pretty (neither would uranium) because it oxidises rather quickly in air. (Not that I would recommend putting it on outside this kind of demonstration. And I would probably invent some excuse to disappear into the nearest lavatory to perform the MSDS-recommended copious handwashing immediately afterwards. But the idea is enchantingly funny.) Double sharp (talk) 08:24, 13 July 2016 (UTC)[reply
        ]
• "The measured properties" you don't need to measure properties for them to be different
  • Removed "measured". Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]

• Wikilinking "percent" is also not needed :)
  • I can't stop laughing now that you've pointed that out! ^_^ Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]

• "Its density has been calculated to be 11.724 g/cm3" -- close to
  WP:WEASEL
  . Who made this calculations, especially since they don't match the reality? Are they even important? (There may be a reason, but it should be explicitly stated: "A simple TWOFG model [could be anything] suggests that the density of thorium should be ..., but it's actually .... The difference arises because...". Or maybe this should be skipped altogether)
  • The 11.724 value is what you would get by directly going from the lattice parameters. With elements like Re with incredibly high melting points, this could be easily explained by it being impossible to cast them in quantity, and sintering leaves microscopic voids. But Th's is not that high, so I do not know what the real explanation is. I've removed it; since Wickleder does not follow up on it, it must not be very important. Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]
    • Why, now that you explain it, it does seem to be catchy for me, at least. It would be great if you found an explanation; I'd be interested to read it as a reader.--
      talk) 21:20, 3 July 2016 (UTC)[reply
      ]
      • I cannot find a better explanation, so I've used this one: it would nicely explain the variability of the experimental results. (Especially since no one would really care for Th; it's dense, but only about as dense as Pb. Double sharp (talk) 07:28, 4 July 2016 (UTC)[reply]

• "showing the continuity of trends across the actinide series" it's not the case for the whole series. "across early actinides"?
  •  Done Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]

• " However, thorium's melting point of 1750 °C is above both that of actinium (1227 °C) and that of protactinium (1562±15 °C): the melting points of the actinides do not have a clear dependence on their number of f electrons" -- but why does the difference exist in first place?
  • Well, there is a trend, it just only works from Th to Pu (the early, quasi-transition-metal actinides). Changed. Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]
    • Now that I've read the rephrased version, I think it can still be better.
    • "However, thorium's melting point of 1750 °C is above both that of actinium (1227 °C) and that of protactinium (1562±15 °C): there is a smooth trend downward in the melting points of the early actinides from thorium to plutonium where the number of f electrons increases from zero to six.[7]"
    • (If I am interpreting this correctly, then this could be rephrased to make smth. like) "Period 7, like other periods, shows a trend of increasing mp throughout early elements as their atomic numbers increase: actinium's mp is 1227 deg C, and, accordingly, thorium's mp is higher: 1750 deg C. At this point, however, a new trend of decreasing mp arises, as the 5f shell fills[a note here on why this actually affects the mp's would be great]: protactinium's mp is ~1560 deg C, and mp's further decrease up to plutonium.
    • A reader's note: "1562±15 °C" could be better if reworded as "~1560 °C", it just becomes easier to read. Also, in the original sentence you use the term "f electron," which you should wikilink to something relevant.

• "Thorium is a soft [...] metal" "Thorium is a soft metal" sure, but there's no need to state that twice in nearby paras. Also, a newline would be great here
  •  Done Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]

• "Among the actinides, thorium has the highest melting and boiling points and second-lowest density (second only to actinium)" would be great to have the discussion on density and mp and bp and trends not scattered throughout one para
  •  Done Double sharp (talk) 16:04, 3 July 2016 (UTC)[reply]

• "The thermal expansion, and electrical and thermal conductivities of thorium, protactinium, and uranium are comparable and are typical of post-transition metals." first of all, thorium is not a post-transition metal, second, the sentence is missing an "and", third, this has to be a clearly distinguished discussion of periodic trends (a para dedicated to just that would be fine). By the way, what are thermal expansion and electrical and thermal conductivities of thorium, are these quantifiable? besides, "typical of post-transition metals" -- is this even high or low?
  • I took this out. Regardless of what the source says, it's not actually true according to Electrical resistivities of the elements (data page). (Also, why on earth does resistivity increase from Th to Pu, even though there are more delocalised electrons?! If I could find the reason, I'd include it!) Double sharp (talk) 14:45, 16 July 2016 (UTC)[reply]

However, I am far from satisfied with this section as a reader (though it is becoming a little better, sure). I gave my initial ideas on reading the section, but I'd want to do more (similarly, I am not satisfied with

How's the current arrangement? Double sharp (talk) 16:14, 3 July 2016 (UTC)[reply]

Fine! Looks fresh and very suitable for thorium. Isotopes as their own section are just fine for Th.--

talk) 21:20, 3 July 2016 (UTC)[reply

]

I planned to mention the metallic radius trend as well, but I decided against it as it's too complicated. You have to take into account that not only are the number of delocalised electrons making a difference, but also the differing structures (12-coordinated for Th, but 10-coordinated for Pa and downright irregular for U, Np, and Pu). This, I think, would be better left to the main article on the actinides. Double sharp (talk) 14:42, 16 July 2016 (UTC)[reply]

I have rethought this section and its organization and will write my ideas soon.--

The next thing to come to my mind would be allotropy. Allotropy actually greatly affects what you describe thereafter (carbon being graphite and diamond being the best example of this). You say something like "thorium only has one allotrope, which is fcc, and it remains fcc until it'a as hot as ... deg C (... deg F, ... K)" or the like. You can probably also describe the stuff like thermal expansion (which is related anyway to lattice parameters, which should also mention) here. Come to think of that, that doesn't exactly fit the title, but then again, make title follow your story and not vice versa. Maybe go with "Mechanical properties"? Then I noticed you had a table; this can be converted into text.\

Hmm, carbon (and tin) are kind of special cases here. Everyone knows graphite from pencils and diamonds from overpriced jewellery; the β→α transition in tin is pretty well-known (tin pest and bursting organ pipes). But of thorium's two allotropes, only the room-temperature one really matters to the average chemist. Does anyone care about the low-temperature hexagonal close-packed allotrope of sodium, for instance? Also, these transition temperatures change greatly with impurities. Double sharp (talk) 10:31, 31 August 2016 (UTC)[reply]

Why wouldn't you say that? "At r.t., thorium is <some form>. Its parameters are blah blah blah. On extreme cooling, it forms a <another form> form, but nobody really cares. Impurities greatly affect allotropy of thorium: example, example."

Then follows a para with stats like density, mp, bp. It would be good to explain why thorium has high values of these paramenters (and this is crucially important). Bulk modulus suits here as well.

I might do a solution like we did at Pb for this, explaining how the [Rn]6d²7s² configuration leads to all this. This is an interesting one. I'd have automatically expected covalent bonding on top of metallic bonding to be the reason, like W, but that can't be right because Th doesn't have a high tensile strength (which would also be raised like W). Didn't I also just say in the article that the reason was because there wasn't much 5f/6d hybridisation in Th (unlike what you get in U), which leads to directional bonds instead of non-directional metallic bonding? Double sharp (talk) 10:31, 31 August 2016 (UTC)[reply]

"Thorium can also form alloys with many other metals." two questions. 1) is it not true for all metals? 2) if you want to specify thorium solves/is solved in other metals and doesn't form copper-lead-like alloys (if this is even the case), do so. Also, the amount of info on this is inadequate. If people actually alloy with anything, then you need more (solubility in metals, for example). If they don't, then a general note in the intro para should be enough.--

Yes, people actually do this. Adding small quantities of Th to Mg metal improves its mechanical strength (ref from Gmelin, though I have to wonder how common this use is today). Th-Al alloys have been suggested as a way to store Th in Th reactors. You get eutectics with Cr and U. Th does not really dissolve in other metals except its "little sister" Ce. (Will add!) Double sharp (talk) 10:37, 31 August 2016 (UTC)[reply]

Isotopes

I'll continue from here.--

• "with more than 83 protons" how did 83 get into this? Since you're writing a detailed section anyway, a little (just a little) context would be fine. ("All elements (except for technetium and promethium) up to bismuth, element 83, are practically stable for any purpose[1], but from polonium, element 84, on, all elements are unstable. Of all isotopes of these elements, thorium-232 is the most stable: its half-life is ..., almost three times as long as the age of the Earth and even a little longer than that of the universe." how's that sound?)
  •  Done Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]

[1] -- by the way, I like how you said "its half-life is so long that its decay is negligible even over geological timespans" in a note; except why is geology important here?

That's about Bi. The idea was that the decay of Bi is negligible, so there is about as much Bi left as there was at the formation of the Solar System. However, with Th and U, we know that what we have left is but a lower fraction of what we had 4.5 billion years ago. Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]

I got it. :) I just liked that new way to describe how long its half-life is. This bothers me every time I have to say smth. about what elements are stable, because Bi is practically stable, but theoretically not! It's certainly better than "super-long" or "so long it can be stable for any purpose" and maybe even a little better than "many orders of magnitude longer than the age of the Universe."

• "However, in deep seawaters the isotope 230Th" we were having a nice introductory talk, and now we're for some reason going into deep seawaters. Since you're discussing isotopes and not geology, this can wait until later. So can the acknowledgment of this second isotope by the IUPAC. Besides, the next para also begins with Th-232! So why break that story by deep seawaters?

• "the last "classically stable" nuclide" even the text acknowledges this is a somewhat original term. Since we're not a book oriented at pros, we could use a note here, or just reword this somehow. Jargon scares people away and this is an encyclopedia for and by everybody. Actually, I think it would be great if you merged the first half of the first para and the first half of the second para into a new para.
  • The reason is that no one thinks of Bi as radioactive, and it is irritating to keep having to note that it technically is. So I explained the term first. Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]
    • Looks good now.--
      talk) 10:25, 4 July 2016 (UTC)[reply
      ]

• "This geographic analogy has often been used by pioneers of superheavy element research, such as Yuri Oganessian, and is the origin of the term island of stability." This whole sentence made me think again if the analogy is even needed. We're only at element 90, after all?
  • Well, the reason I put this sentence in was so that it would be obvious that this analogy was not OR. I've relegated it to a footnote, since it feels very tacked-on.
  • As for why the analogy is here, it's because Th and U are widely considered to be an "island of relative stability", as you will see if you look at the half-lives of the trans-lead elements: you can see this in all those island-of-stability pictures too. See this for example. Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]
    • Hmm. I see that the term still is more commonly used for the superheavies even with that "relative" (and one source refers to, unexpectedly, Iran and something about oil(?)). I suggest you move all of that into a long note. Or best skip altogether, this feels not relevant here. I just took another read---yes, this feels not needed, since Th is element 90. This could be revised twenty or so elements later.--
      talk) 10:25, 4 July 2016 (UTC)[reply
      ]
      • The main reason I want to say it is so that I can talk about this region around A = 230–250 and Z = 90–96, give it a name (as two of those search results do), and say why it should be singled out for stability (again, shell effects). If not you would expect it to be like Po and Rn; the strong force can't reach all the way across, so bits fall off (alpha decay) until it's small enough that this is possible (reaching Pb or Bi). But with Th and U, we are completing a nuclear shell, so this alpha decay is inhibited. Double sharp (talk) 12:14, 4 July 2016 (UTC)[reply]
        • >"as two of those search results do" but that's two! You see, there is a reason why it's only two results :) you don't need a special term to discuss something, you can just say "thorium to (around) curium" or the like. You don't need to have a para of poorly relevant talk to just invent a synonym which is, by the way, ambiguous, as the Google Books search results tell.
        • So am I correct in that the struck text is just introductory talk?
        • The line of stable nuclides, that is mostly continuous from hydrogen to lead (with breaks at technetium and promethium), plummets immediately after bismuth with its extremely long half-life of 1.9 × 1019 years. The next element, polonium, has a half-life of only 130 years (209Po), and there follows a three-element gap of extreme instability where the longest-lived isotope, 222Rn, has a half-life of only four days.[9] (this, by the way, has partly already been covered in the previous para) By geographical analogy, bismuth is at the shore of the continent of stable nuclides, with a following strait of instability centered on radon. A continental shelf continues, nevertheless: shallows begin to appear at radium, with a half-life of 1600 years, that rise to form significant islands towering over the sea at thorium and uranium, forming an archipelago with the lesser islands at the actinides neptunium, plutonium, and curium which have half-lives of millions of years. The islands then recede back into shallows by californium (half-life 900 years), and by the end of the actinide series the open "sea of instability" yawns before the shore, where the mutual electromagnetic repulsion of protons finally cannot be overcome, and the nuclides quickly succumb within a few milliseconds to spontaneous fission.[12][13][d] The reason for the existence of this "island of relative stability" around thorium and uranium is because the most stable isotopes of these elements have closed nuclear shells;[14][15] nevertheless, since thorium and uranium have more protons than lead and bismuth, their nuclei are thus still susceptible to alpha decay because the strong nuclear force is not strong enough to overcome the electromagnetic repulsion between their protons.[16]
        • You won't lose anything if you just say something like "Since thorium and uranium have more protons than lead and bismuth, their nuclei are thus still susceptible to alpha decay because the strong nuclear force is not strong enough to overcome the electromagnetic repulsion between their protons. However, they have closed nuclear shells: this is the basis of the stability of both elements. (since you described that in the previous para)" (also, this could use some details, but that could be hardcore physics, so I can't tell; still, are these available?). You're not writing
          talk) 12:43, 4 July 2016 (UTC)[reply
          ]
          • OK, cut the introductory material: you make sense. It is also not quite agreed on how far this "island" should extend: it seems from those two books that Th and U are the main things, and Np, Pu, and Cm are only getting the benefits in a horseshoes-and-kisses kind of way. So I made it talk about only Th and U, the only two primordial radioactive elements. Double sharp (talk) 13:05, 4 July 2016 (UTC)[reply]
            • Looks great now.--
              talk) 13:21, 4 July 2016 (UTC)[reply
              ]

• " in the 4n decay chain which includes isotopes with a mass number divisible by 4" ", hence the name"
  •  Done Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]

• "lead-212 (212Pb)" by the way, you should use one system to refer to nuclei throughout the article: it uses both.
  • Switched to the ²¹²Pb format throughout. Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]

• "The most stable of them (after 232Th) are 230Th" here, that's a nice place to move that seawaters talk to
  • Done. (And I should try to find a reason why ²³⁰Th occurs there...) Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]
    • Oh yeah, I missed that :) please do.--
      talk) 10:33, 4 July 2016 (UTC)[reply
      ]

• "g·cm−3" this is very minor, but isn't g/cm3 just nicer?
  • True. Changed. Double sharp (talk) 07:20, 4 July 2016 (UTC)[reply]

• "bare critical mass" this is surely wikilinkable to something relevant. Besides, could you make it half a sentence longer to it would be easier to understand? (I remember what we're talking about from physics at school, but surely not everyone paid attention back then)
  • Linked. Double sharp (talk) 07:29, 4 July 2016 (UTC)[reply]

In general, a nice section.--

• "The isotope 229Th has a nuclear isomer (or metastable state) with a remarkably low excitation energy,[16] recently measured to be (7.6 ± 0.5) eV.[17]" This sentence seems a little out of place. Either a small introduction of half to one sentence or leaving it out (which I prefer at the moment) will do.--
  talk) 10:33, 4 July 2016 (UTC)[reply
  ]
  • I separated it out, adding a brief intro like the other element articles about Th also having 3 meta states. Now the reason I mention this – and I can't believe I forgot – is that this is actually so low that if it underwent isomeric transition, the gamma ray emitted would be in the UV range! (Added this.) Double sharp (talk) 13:11, 4 July 2016 (UTC)[reply]
    • Well done!--
      talk) 13:21, 4 July 2016 (UTC)[reply
      ]

• "Thorium has a characteristic terrestrial isotopic composition, consisting largely of 232Th and a little 230Th" we already got this, too
  •  Done Double sharp (talk) 13:57, 4 July 2016 (UTC)[reply]

• some wlinks to nuclides actually redirect to Isotopes of lead or Neptunium, why have them in first place?
  • Removed. Double sharp (talk) 13:57, 4 July 2016 (UTC)[reply]

otherwise the section looks great! except a few comments are still waiting to be completed (like that IUPAC one).--

• Done it (I should be more organised...) Double sharp (talk) 13:57, 4 July 2016 (UTC)[reply]

• final one: "It is detectable because while its parent 238U is soluble in water, 230Th is insoluble and thus precipitates to form part of the sediment." there's a double subordinate clause! this is a call to rewrite the sentence to improve the prose quality.--
  talk) 14:01, 4 July 2016 (UTC)[reply
  ]
  • Fixed Double sharp (talk) 14:11, 4 July 2016 (UTC)[reply]

Regarding exactly what happens beyond Bi: here's my totally-not-expert guess at a bird's-eye-view of the nuclides chart. If you look, alpha decay starts to infect the light isotopes of Te–Xe, and then it assaults some of the early lanthanides (all "stable" isotopes of Sm and Eu should undergo it). Then it sneaks up at the proton drip line in the 5d transition metals, and its reign rapidly expands until the magic numbers can no longer save you past Bi, and at Po it erupts and takes over, driving out poor electron capture. Then if you look at the lines of beta and alpha stability, you see the horrible truth: they diverge from each other past the magic number effects culminating at Pb. So if you look at ²³²Th and ²³⁸U, they are actually close to the heaviest isotopes of these elements we know (²³⁸Th and ²⁴²U). They get a magic number boost, but everything around them dies quickly of beta emission. Then we face another attack on the beta-stability line by spontaneous fission from ²⁵⁰Cm onward, and the island comes to an abrupt halt. (I may be totally wrong about this.) Double sharp (talk) 14:28, 4 July 2016 (UTC)[reply]

• I also suggest leaving the
  talk) 08:06, 6 July 2016 (UTC)[reply
  ]

• Why is radiodating added? of course, it is related to isotopes, but is it a big thing? I think that hardly a brief mention is enough (check, for example, Lead#Isotopes and how radiodating is mentioned there).
  • Well, I only have one paragraph, and it seems to me that it follows how we mentioned earlier that ²³⁰Th and ²³²Th are the only two important isotopes of thorium in nature. (Also, I think isotopes and radiodating are more important for Th and U than for stable elements. For example, the ²³⁸U:²³⁵U ratio has changed substantially over time because of the shorter half-life of the latter.) Double sharp (talk) 10:43, 31 August 2016 (UTC)[reply]

It's the position I would stand on, but I won't argue as long as you're confident in your choice.--

talk) 15:49, 1 September 2016 (UTC)[reply

]

• "However, ten years later, he retracted his findings, as the mineral in question proved to actually be an yttrium mineral" was he the first to realize he'd made that mistake, or did someone point him to that?
  • According to the Fontani reference, he was very cautious about the 1815 discovery, as he was himself unsure. (Apparently he did not even announce the name "thorium" in the paper; given that Wickleder and that old great source Weeks both give it, presumably he did not release the name, but may have written it down in his laboratory notebooks as a good idea for an element name.) Unfortunately many of the secondary sources are frustratingly vague about all of this, and I cannot really access Berzelius' notebooks myself to do original research! Double sharp (talk) 13:33, 7 July 2016 (UTC)[reply]

• speaking of which, why did he even make that mistake? was there a specific reason?
  • No idea, but he was not really sure himself, as I said. (He had earlier been involved with another false discovery, gahnium, which turned out to be nothing more than zinc oxide. He was in his mid-twenties and was just flush from the success of discovering cerium, and was not careful enough: no doubt he learned from his mistake, and that was why he was so cautious about the 1815 "discovery", not even giving it a name in public, as if he did not have complete faith in it.) Double sharp (talk) 13:33, 7 July 2016 (UTC)[reply]

• "the mineral was named kenotime" but that happened after 1825? what was the mineral referred to between 1815 and 1825? genuinely curious. and who came up with that name?
  • Apparently nobody named it before 1824 (sorry, there was a mistake: I cited Berzelius' paper now). I added the origin of the name. (Presumably nobody named it before further deposits were discovered in 1824, per the Mindat source.) Double sharp (talk) 07:12, 6 July 2016 (UTC)[reply]
    • Nice. Such details are (almost) always great.--
      talk) 09:01, 6 July 2016 (UTC)[reply
      ]

• "In 1828, Morten Thrane Esmark found a black mineral" and what led to that? again, really want to know
  • Added. He was a priest and mineralogist who studied the minerals around Telemark, where he served as vicar. He usually sent the most interesting specimens, such as this one, to his father. Double sharp (talk) 07:16, 6 July 2016 (UTC)[reply]
    • Great one, thank you.--
      talk) 07:29, 6 July 2016 (UTC)[reply
      ]

• One more for now: how long did it take to get Th recognized as an element by everyone? Nowadays, we have IUPAC that is sort of the ultimate judge, but there was none back then. Did anyone use the idea that that "thorium" of 1815 was an element? How long did it take for that idea to catch up after 1829? (It's hard to say if someone would use that knowledge anyways if nobody contacted the element and there wasn't a full-scale periodic table yet without researching. If that's the case, still mention that in the text; it will compliment the later parts on Mendeleev's and Seaborg's tables)
  • I don't think anyone would've doubted it the second time, after Berzelius could hold a sample of (admittedly not very pure) thorium in his hands: he was very respected by that time. The first time, given his own uncertainty, people must have doubted. But annoyingly I cannot find a source for their reactions: it does not seem like the sort of thing that would have been recorded! Double sharp (talk) 16:09, 8 July 2016 (UTC)[reply]
• Speaking of Mendeleev, it would be cool to briefly mention (maybe even in a note) if thorium was included into other tables of mid-19th century. Also, it'd be nice to mention that Mendeleev's didn't get recognized immediately, which makes adding info on other tables even more relevant.--
  talk) 07:29, 6 July 2016 (UTC)[reply
  ]
  •  Done (and given that Th was thought of as associated with the rare earths at that time, whenever Th fails to appear, the rare earths similarly are not present). Double sharp (talk) 16:09, 8 July 2016 (UTC)[reply]
• "While cerium was soon removed from the main body of the table and placed in a separate lanthanide series, it was not until 1945 that Glenn T. Seaborg realised..." if I were to write this, I would definitely leave that util we move to 1945. When you give the story and make it follow the chronological order of events, it is quite natural to introduce concepts in the order that they appeared. If you mention that 1892 idea in the main text, then introduce the concept at that moment. If you leave it in a note, then mention it when Seaborg rolls into the story. (By the way, the 1892 note looks absolutely cool. This is kind of a detail I'd want in a FA of mine.)

• Also, I'd move the isolation (which is, by the way, a nice addition) to a new paragraph that is located per Th's chronology, given we're talking about a 1914 event. I'd start it like "Although Th was discovered in 1829, it wasn't isolated at that point; and either nobody even tried before the 19th century or nobody succeeded (depending on what the actual case is; if there were attempts you can find, please add them). For the first time, Th was isolated by a XXXian physicist(?) D. Lely, Jr. [this man is tougher to google than you'd expect; please spell out the names] and and YYYian physicist(?) L. Hamburger in 1914. They performed the isolation using ... and described some basic properties of thorium metal."
  • I am really not hopeful at finding their names: even their original paper describing their results doesn't spell them out, and nobody who cites them thereafter spells them out either. But I did at least find out their method (now to be included). Their real accomplishment was the isolation of 99%-pure thorium, as while others had tried earlier, there still remained significant Ce and U impurities that went unnoticed because of their similar chemical properties (particularly ThO₂ vs. CeO₂ and UO₂). Double sharp (talk) 12:22, 7 July 2016 (UTC)[reply]
    • What I would do now is to write directly to Zeitschrift für anorganische und allgemeine Chemie and ask them if they could help spell out the names. They have their archives, surely they can help. (If you don't do it in a few days and signal as such, I will.)--
      talk) 08:00, 8 July 2016 (UTC)[reply
      ]
    • The End of the Artkle gives a place of work of the two authors: Eindhoven, Holland, Chemisches Laboratorium der Philips’ Metall- Glühlumpenfabrik A.-G. (Chemikal Laboratory of the Philips Metal-Lightbulb-Factory- AG)--Stone (talk) 19:57, 24 July 2016 (UTC)[reply]

• "The space thorium formerly occupied in the periodic table under hafnium is now occupied by the transactinide rutherfordium.[41] Today, thorium's similarities to hafnium are still sometimes acknowledged by calling it a "pseudo group-4 element"." this would be more suitable in a note
  • I'd put the first sentence in a note, indeed, since it is more about Rf than Th. Nevertheless I am not so certain about relegating the second that one, because it does illustrate how similar Th is to Ti, Zr, and Hf, and how useful that classification is. Really, if you only look at Th, Pa, and U, they are far more like transition metals than lanthanides: group 3 cannot really fit these three actinides well (if you use the 15LaAc interpretation of the table), because of their maximum and common +4, +5, and +6 oxidation states respectively. (In fact, I believe this was still a matter of controversy at the time of the beautiful Soviet popular-science book I linked to you – look for "Where is Thy Place, Uranium?" ^_^) Double sharp (talk) 12:22, 7 July 2016 (UTC)[reply]
    • This sounds reasonable, yes, so will do as well.--
      talk) 08:22, 8 July 2016 (UTC)[reply
      ]

• There's little left to describe in this section. Want to know much more about the uses. Nuclear weapons and energy are absolutely missing. "In the early history of the study of radioactivity, the different natural isotopes of thorium were given different names. In this scheme, 227Th was named radioactinium (RdAc), 228Th radiothorium (RdTh), 230Th ionium (Io), 231Th uranium Y (UY), 232Th thorium (Th), and 234Th uranium X1 (UX1).[18] This reflects that 227Th and 231Th occur in the decay chain of natural 235U (the actinium series), 228Th occurs in the decay chain of 232Th (the thorium series), and that 230Th occurs in the decay chain of 238U (the uranium or radium series)." -- think this belongs here, except needs to be re-written into a nice story: after you mention the first discovery of radioactivity, it generally makes sense to say something along the lines of "Research on radioactivity sparked like fire, and many new nuclides have been found that received their own names: ... At one moment [say when], however, it became apparent that all of these were isotopes of the same element as the nuclide that was at that time referred to as "thorium" [Th's only natural one, 232Th]. As such, they were "combined" into a single established element 'thorium'." (the wording could've been better, but you get the idea.)--
  talk) 09:55, 7 July 2016 (UTC)[reply
  ]

• "Meanwhile, Niels Bohr's theoretical model of the atom and its electron orbitals indicated that the seventh row of the periodic table should also have f-shells filling before the d-shells that were filled in the transition elements, like the sixth row with the lanthanides preceding the 5d transition metals." does it? I am not familiar with Bohr's original work, despite the popularity of the concept in general. Did Bohr really (even if indirectly) predict the 5f series?
  • Yes, he did! (His table even has blanks after uranium, and he explicitly notes that 118 would be the next noble gas after radon! How cool! But not for this article, of course: but I suppose it would make a good addition to the 118 article that Bohr was the first figure to take the possibility of such a high-numbered element seriously, a few years before Charles Janet and his table that extended to 120.) However, while he did think that 5f should fill and make row 7 as long as row 6, he looked at the chemical properties of Ac–U and inferred that 6d and 5f would have crossed energy levels, and that 5f should not start being occupied favourably until Pu. So he seems to think of Th as a 6d element, but correctly placed it under Ce in his table. Double sharp (talk) 09:08, 8 July 2016 (UTC)[reply]
    • Wow, how cool. Yes, it would be great to add that to
      talk) 09:20, 8 July 2016 (UTC)[reply
      ]
      •  Done (also, added Bohr to the infobox as the one who predicted 118, just like Mendeleev predicted Ga) Double sharp (talk) 09:40, 8 July 2016 (UTC)[reply]
• " This occurs because the 5f orbitals are then relativistically destabilised and delocalised and are thus able to participate in chemical reactions to an extent similar to the d-electrons of the transition metals." sure, but it's a distraction from the main story, let's put it into a note
  •  Done Double sharp (talk) 09:08, 8 July 2016 (UTC)[reply]

• " he took part in, that Glenn T. Seaborg" I (as well as many prose masters) never liked a sentence in which a man is referred to as "he" before we even know who he is.--
  talk) 08:22, 8 July 2016 (UTC)[reply
  ]
  • Fixed! Double sharp (talk) 09:08, 8 July 2016 (UTC)[reply]

• I've thought about it for some time. One thing I'd want to get implemented is to treat the 20th century improvements as further development of the atomic theory. So I imagine a para starts off like "In the late 19th/early 20th century, the
  rare earth metals
  [please add this remark!]. Someone tried that in 1892 and failed; the actual isolation happened in 1914 by X and Y [have you written to that German journal yet to get their names, or should I?]. In 1927, someone else made further improvements to the purification process, obtaining even purer thorium")
  • Yes, I think you should write to them. Double sharp (talk) 13:01, 11 July 2016 (UTC)[reply]
• The same comment, generalized: Since what happened around Th in the 20th century happened within a very remarkable and easily distinguishable topic of radioactivity, it's a great idea to try to make that theme resounding throughout the description of that period.--
  talk) 09:56, 11 July 2016 (UTC)[reply
  ]

• • I'm still here; I've just been reading about the Th fuel cycle to see how much of it is reality, in response to Stone's comments. Double sharp (talk) 03:07, 9 August 2016 (UTC)[reply]

Occurrence

I haven't actually read the section yet, but there's a comment I want to give out right away.

I'd been thinking about it for some time until I realized the best order of section generally is: Physical (usually with two subsections, Bulk and Isotopes, which separate sections here; this makes no difference) -- Chemical -- Occurrence -- History -- Production -- Uses -- Bio/Precautions. Physical is the most general section of all, and it may help explain we'll read later. Then chem, also general and related to phys; then occurrence (which will benefit from the context by Isotopes for formation/stars and Chem for terrestrial occurrence). Then history, which probably will benefit from occurrence. Then production, usually related to history. Then Uses (makes sense to put those directly after Production). And then Bio as a great way to end the article. (I also think that the current Chem is too large, but I'll come to that later.)--

• the first half-sentence is bad. "Th has been around for >4.5B years (link to age of Earth), being older than the Earth." so... How long exactly has thorium existed? What does the Earth have to do with this at this point if you then talk about dying stars?
  • It should have been made with the first supernovae, ~10¹⁰ years ago. Cut the stuff about the Earth. Double sharp (talk) 16:34, 21 July 2016 (UTC)[reply]
• Immediately after this introduction, I'd move to the how of Th formation (the r-process; also, you don't need to mention the other processes since they're not relevant here), and then to the where, and then to general statistics (ppm in the Universe, etc.)--
  talk) 10:58, 21 July 2016 (UTC)[reply
  ]
  • Edited. Now I just talk about the r-process alone and why it is the only one for Th, implying that it is only made in supernovae. I also notice a cool fact that Th is almost as abundant on Pb on Earth, but is far less abundant in the Universe; where should I add that? (Seems to straddle both sections.) Double sharp (talk) 16:35, 21 July 2016 (UTC)[reply]
    • The Earth is a part of the space, so first the intro (Formation) and then the specifics (Earth and anything related to it). So I'd probably put it in the second subsection. (Why is that, by the way?)--
      talk) 20:48, 21 July 2016 (UTC)[reply
      ]

• by the way, think if you want to use the Oxford comma and make the article comply.--
  talk) 08:58, 22 July 2016 (UTC)[reply
  ]

• what is the purpose of the table with relevant occurrences? as of now, the first thing I see is that lead is abundant, but it should be something about thorium, right?
  • It's a little hard to make this point with the numbers; a graph would work better. (Though I'm not sure how good the current replacement is.) I'm not really sure what I should be comparing Th with, actually, other than U, because everything else gets produced in multiple ways. Double sharp (talk) 11:50, 22 July 2016 (UTC)[reply]
    • Then don't. In
      talk) 12:17, 22 July 2016 (UTC)[reply
      ]
      • I left it as the big graph, illustrating that just as one would expect from its high atomic number after the trench of instability after bismuth, thorium is rare. There isn't much else to say for occurrence in space. Double sharp (talk) 12:43, 22 July 2016 (UTC)[reply]
        • Hmmm. An interesting (good) solution.--
          talk) 13:06, 22 July 2016 (UTC)[reply
          ]
• " This is because thorium, being a lithophile, is likely to form oxide minerals that do not sink into the core, unlike the platinum group metals that are more abundantly produced by the r-process.[70]" I don't understand (I actually don't, please explain here), why is this the reason?
  • Now that I think about it, this isn't actually a complete explanation. Okay, so while the r-process would give you lots of late 5d transition metals and very little Th, the fact that Th stays on the surface while the 5d transition metals don't means that you see more Th on Earth. This is fine, but it doesn't really seem like it explains how Th somehow becomes as common as Pb on Earth. There is a big jump there, as you can see if you look at the graph! I will keep looking. Double sharp (talk) 12:43, 22 July 2016 (UTC)[reply]
• "odd-numbered" I suggest explaining in a note (which you're free to take from lead) why that even matters
  • OK. Double sharp (talk) 11:50, 22 July 2016 (UTC)[reply]
• "and of these only tantalum is also less abundant than uranium, being in fact the rarest element in the Solar System" not relevant here. Sure, there are many nice facts about what's around thorium, but most of them don't belong here since you're writing an article called
  talk) 10:32, 22 July 2016 (UTC)[reply
  ]
  • Cut. Double sharp (talk) 11:50, 22 July 2016 (UTC)[reply]

• By the way, that fact that Th compounds are not very soluble may be relevant here, but the fact that Ba compounds are certainly isn't.--
  talk) 10:44, 29 July 2016 (UTC)[reply
  ]
  • Cut as a lame attempt at handwaving. (I confess I still am unsure about exactly what is going on here.) Double sharp (talk) 13:18, 29 July 2016 (UTC)[reply]

Chem

This section is so long. So long.--

Part of the problem is the opening, which is where I am trying to set the stage for the properties of Th, but instead ends up rambling all over the place now that I look at it. Similarly to the way you give an introductory primer on Pb in that article, I would think that the most important aspects that should be taken away by the reader about Th's chemistry are (1) it is practically always in the +4 state, giving away all four valence electrons, and acts as a hard acid like a typical highly-charged cation; this is mitigated by (2) it is a large cation, leading to high coordination numbers and varied geometry (e.g. 11-coordinated nitrate, 10-coordinated oxalate, 14-coordinated borohydride).

I could go a little further: for example, (1) happens for Th but not Ce because 5f is relativistically destabilised more than 4f. But these two are the main things that I would say would count as a brief introduction to Th's personality. (I would still note that Th, U, and Pu are quite approachable, unlike the other actinides with their murderous self-destructive urges, which accounts for the differing knowledge of their chemistry.) There are a few chemical trends across the actinides (e.g. increasing reactivity) but since Th is the first of them, it's not so relevant: in any case Th is already reactive enough to tarnish in air, so the only difference with the later ones is how quickly this happens. (Ac does not conform to that trend at all.) Double sharp (talk) 16:09, 21 July 2016 (UTC)[reply]

I would split the overview for the main Th article into inorganic and organomteallic compounds after this intro. Then I would simply write that the binary compounds can mostly be prepared just by direct reaction from Th and the nonmetal you want upon heating. The most useful are with B, C, N, and Si, which are chemically stable and refractory and hence are good choices for nuclear fuels. Then thoria needs a whole paragraph to itself. Halides can all be lumped in one paragraph, with a brief note regarding how ThF₄ is different from the other three, and the fact that the lower iodides are electrides.

I don't think we need to mention the usual spectroscopic stuff because Th⁴⁺ is basically always colourless – though I'll keep it in mind for Ce⁴⁺ in the Ce article, where I need to explain why it is orange (metal→ligand charge transfer). The hydroxide and its decomposition can be mentioned when covering (1) in the opening paragraph. (Do we need to mention the false Th³⁺? Or just make it a note?)

Finally organometallic notes that this is focused on cyclopentadienyls and cyclooctatetraenyls (mention thorocene, it's the easiest to explain), and say that 5f involvement means significant covalent character (hence this is the only chance to get to the +3 and +2 states stably). Apart from this, the chemistry is poorly known (no known structure for tetrabenzylthorium, unsubstituted tetramethylthorium not even known). How does this proposed shortened version sound? Double sharp (talk) 16:26, 21 July 2016 (UTC)[reply]

I see what I would want to do, but let's get to it after we're done with Occurrence, okay?--

talk) 17:30, 21 July 2016 (UTC)[reply

]

How is it now? Double sharp (talk) 15:06, 23 July 2016 (UTC)[reply]

I gave it a very brief look. Much, much better, though I see potential for improvement and detailed reading is yet to follow. More on this in two or three hours.--

talk) 16:32, 23 July 2016 (UTC)[reply

]

• "Four atomic orbitals are theoretically available for the valence electrons to occupy: 5f, 6d, 7s, and 7p. However, the 7p orbital is greatly destabilised and hence it is not occupied in the ground state of any thorium ion." how come you say 7p is "theoretically available for the valence electrons to occupy" when it "is greatly destabilised and hence it is not occupied in the ground state of any thorium ion"? seems logically inconsistent. why isn't, say, 8s theoretically available?
  • Wickleder et al. say it this way, but I agree it looks silly. The main point is that 5f, 6d, and 7s are close in energy, while 7p is a lot higher, but this is not really unexpected. Removed 7p. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "Despite thorium's position in the f-block of the periodic table, it has an anomalous [Rn]6d27s2 electron configuration in the ground state, as the 5f and 6d subshells in the early actinides are very close in energy, even more so than the 4f and 5d subshells of the lanthanides: in fact, thorium's 6d subshells are lower in energy than its 5f subshells, because its 5f subshells are not well-shielded by the filled 6s and 6p subshells and are destabilised. The closeness in energy levels of the 5f, 6d, and 7s energy levels of thorium result in thorium almost always losing all four of its valence electrons and hence occurring in its highest possible oxidation state of +4." nice talk (really nice), but I thibk adding a word on the SO interaction helps a bit to a reader not familiar with this. (What's been said in lead, for example, is enough.)
  • OK, added. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "This behaviour much more similar to the transition metals zirconium and hafnium than to that of the lanthanide cerium..." I think four words are missing here: "therefore" (because the previous talk explains the reason for this), "is" (English grammar ;), and "those of" (reads better)
  • How is it now? Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "Although nuclear instability is a major problem for most of the radioactive elements, resulting in their compounds being hazardous to handle and study and being only available in small quantities and being highly prone to radiolysis, the build-up of daughters and heat generation that alter observed properties, thorium, uranium, and technetium are so stable that these problems do not apply to their compounds." sooooo... it's not a big deal here, so why even mention it?
  • Well, it goes back to what you said on your talk page about Th and U being almost normal elements. (Even Tc hasn't been investigated quite as well, probably because you need to make it artificially, while you can just mine Th and U out of the ground.) So I edited it down to "Thorium and uranium are the most investigated of the radioactive elements because their radioactivity is slight enough to not pose major problems of handling and accessibility." Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "Thorium is a highly reactive and electropositive metal. At standard temperature and pressure, it is slowly attacked by water..." the first thing I imagine when I hear "reactive metal" is its oxidation by the air... let's start with that. the section is fine otherwise.
  • OK. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "When heated, it emits intense blue light" why?
  • Incandescence; added. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• In general, Inorganic compounds is okay. As of now, it'll probably pass an FAC.

• "The heavier pnictogens also form binary thorium compounds." first, I suggest not using terms "chalcogens", "pnictogens", etc. when possible ("halogen" is a well-known term by anyone, in contrast to these). Also, what do we get? Is there (say) Th₃Bi₄?
  • Yup! There is Th₃Bi₄! (And also the analogous N, P, As, and Sb compounds.) There are also binary compounds with Si and Ge. The contents of Gmelin are a good way to see at a glance how much is known for each element. (Notice how thorium and uranium drown out all the other radioactive elements. Even technetium is simply not in the running.)
  • The reason I have these little throwaway sentences, that are expounded more on in
    compounds of thorium, is that I mentioned back at the beginning of this section that you could get thorium compounds with most nonmetals by just heating the elements together, and I felt a little bound to say which elements you could do that with. So now you will notice that I cover the hydrides, oxides, and halides in detail, and just quickly mention in these throwaway sentences what other elements you can get (B; C, Si, Ge; N, P, As, Sb, Bi; O, S, Se, Te). I at least linked chalcogen and pnictogen and defined which elements we are talking about here in parentheses (excluding Po), so it's not so bad. Double sharp (talk) 03:58, 24 July 2016 (UTC)[reply
    ]
• "Thorium is the only element that forms a hydride higher than MH3" what about stannane and plumbane, not to mention methane?
  • You're right. I suppose Morss (the source) was only thinking about the left end of the table and completely forgot about the right end. CH₄ isn't a hydride (carbon is a little more electronegative), but your point stands perfectly about SnH₄ and PbH₄. Double sharp (talk) 03:58, 24 July 2016 (UTC)[reply]
• "In aqueous solution, thorium occurs exclusively as the tetrapositive aqua ion [Th(H2O)9]4+, which has tricapped trigonal prismatic molecular geometry:[47][48] at pH < 3, the solutions of thorium salts are dominated by this cation." as is, this is very inconsistent. So Th exists in solutions solely as [Th(H2O)9]4+, and then solution of Th salts are dominated by this ion only "at pH < 3"? what happens under other pH values? this -- "predominantly to [Th2(OH)2]6+ in solutions with pH 3 or below" -- is further confusing.
  • I redid this properly; it was confused. AFAIK, when pH is below 3, you get practically all [Th(H₂O)₉]⁴⁺, but as you raise the pH beyond that, the hydrolysis starts to happen and can go all the way to the hydroxide. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• At this point, I must say I underestimated the section at first. Not only it's undergone a great improvement, you've written a very solid section. This is very interesting to read and seems pretty characterizing to me.

• "more well-known" better-known?
  • Good point. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "Although these f-series cyclooctatetraenyls are not isotypic with the d-series cyclopentadienyls, including the more famous ferrocene, they have very similar structures, and were named to emphasise this resemblance.[2]" seems a little out of place here
  • Well, I was trying to say that despite the name, thorocene isn't exactly like ferrocene (because ferrocene seems pretty well-known), but this is more about COT sandwich compounds in general than thorocene, so I've removed it. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "the temperature of dry ice" are Celsius and Fahrenheit available?
  • Not in the source, unfortunately! Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "piano-stool structure" unfortunately, I can't imagine that :(
  • Added a diagram. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• "ThIII(C5H5)3 and ThIV(C5H5)4" is it necessary to show the oxidation states? I mean, why? you even make an accent on that later?
  • Removed. Double sharp (talk) 04:28, 24 July 2016 (UTC)[reply]
• As I said, an exceptionally good section.--
  talk) 19:01, 23 July 2016 (UTC)[reply
  ]

There is not that much demand for Th, so companies do not make it as the main product: this must be why I didn't find any listings. The meagre quantities we do have are made as by-products of the production of Ln and U. Added some extra information regarding countries and tonnage. Double sharp (talk) 07:28, 29 July 2016 (UTC)[reply]

It would still be cool to add such a basic description in the beginning of the section. I see you have the info, I just think it'd be better to move it up the text. by the way, here are comments re that para:

• " Half of this thorium produced is used in gas mantles." belongs to a different section
• "Nevertheless, production could easily be increased, and probably would be" second conditional? so there are few chances of that?
• "Present knowledge of the distribution of thorium resources is poor because of the relatively low-key exploration efforts arising out of insignificant demand. India is believed to possess the largest supply of thorium in the world, making up almost half of world reserves, but not even a thousandth of these reserves have been extracted.[98]" belongs to another section--
  talk) 21:49, 31 July 2016 (UTC)[reply
  ]

This was copied from

Diphosphate does not mean two PO³⁻
₄ anions; it refers to the pyrophosphate anion P
₂O⁴⁻
₇. Indeed ThP₂O₇ is known to exist, unlike the supposed compound with the formula stated. Changed. Double sharp (talk) 07:18, 29 July 2016 (UTC)[reply

]

• Also, why is so little attention paid to the first method comared to the second one? is that fair? which one is used more commonly?--
  talk) 21:49, 31 July 2016 (UTC)[reply
  ]

I found the original USGS report and will change some things. (Most production relies on monazite because it is mined for the rare earth content and Th is produced as a by-product. If demand for Th ever increased, we would probably be relying on thorite instead.) Double sharp (talk) 06:50, 2 August 2016 (UTC)[reply]

I'll wait for the change to come and skip the section for now.--

talk) 11:15, 2 August 2016 (UTC)[reply

]

• "One notable exception is the use of thoria..." this caught me. Why is it "thoria" and not the systematic "thorium dioxide"? If the former is actually more commonly used among those who use it, you should explicitly say that on first mention (which now is "In air, thorium burns to form the simple dioxide, ThO2, also called thoria or thorina." See, you clearly refer to ThO2 as "thorium dioxide" which is also called "thoria", and then it suddenly becomes the main name) or here.
  • Apparently so, yes. Double sharp (talk) 12:38, 17 August 2016 (UTC)[reply]
• "The electrodes labelled EWTH-1 contain 1% thoria, while those labelled EWTH-2 contain 2%.[102]" too detaile here

• Also, how does it work and shouldn't it be introduced after you say ThO2 is so refractory?

• "Only a few elements (including tungsten and carbon) and a few compounds (including tantalum carbide) have higher melting points.[40]" why mention tantalum carbide, all of a sudden? actually, same question regarding W and C

• "This means that when heated to high temperatures, it does not melt, but merely glows with an intense blue light" why? surely I thought I knew why (though a quick explanation in a note would not hurt, as many people are not aware of colors of hot beyond red, yellow, and white), but how does addition of cerium dioxide change that?

• "This property of thoria means that thoria and thorium nitrate" a property of thoria means nothing for thorium nitrate
  • Actually it does, because at such high temperatures Th(NO₃)₄ will thermally decompose to ThO₂, NO₂, and O₂. So sometimes Th(NO₃)₄ is used instead, since it will generate thoria on heating. Double sharp (talk) 12:38, 17 August 2016 (UTC)[reply]
• "This property of thoria means that thoria and thorium nitrate are used in mantles of portable gas lights..." even the last thing aside, this is still incorrectly worded. "This property has been exploited/become the basis/anything in its use in mantles of portable gas lights and something"

• "200 mrem (2 mSv)" I've been explained what "mrem" is, but what is "mSv"? At least link to
  sievert (unit)
  or something. Also, rem and sievert are different units and measure different things. The equivalent to sievert would be roentgen. (Don't know what would be the best thing to do; just be sure whatever you will is the best)

• "A study in 1981 estimated that the dose from using a thorium mantle every weekend..." come to think of that, that would fit just nicely into the para in History where we discuss the phaseout

• In general, again, this section is difficult to read because it's poorly structured. I'll better reshuffle it and then add my comments.--
  talk) 13:57, 6 August 2016 (UTC)[reply
  ]

It wasn't as bad as I thought, just one misplaced para ruined the flow.--

talk) 14:38, 6 August 2016 (UTC)[reply

]

• At this point, I finally realized one thing that should've become clear to me long ago is not clear yet and as obvious as it sounds now that I did understand it, I never thought in detail before and it wasn't as clear (and your text should be clear from the beginning). Thorium gas mantle is a portable source of light that requires no electricity. Aha! This simple fact changed everything. But why is thorium so good for this use? (I don't know yet.)--
  talk) 15:31, 6 August 2016 (UTC)[reply
  ]

Is it a real application when it is only a possible use? For me all the nuclear applications belong at the end of the section. There are real but slowly phasing out applications. The nuclear applications are planned for the futur or they are research applications long closed down. The thorium fuel cycle is no more real than the breader reactors of the uranium fuel cycle. The radio isotop dating in the uranium article is part of the isotopes section and there it fits much better than in the application section. --Stone (talk) 19:03, 31 July 2016 (UTC)[reply]

It is not just a possible use; there really is one active reactor today in India using Th as well as U. Anyway, if Greenwood and Earnshaw (as well as the Wickleder review) put it under their own sections for applications (radiometric dating is also put there in Wickleder), it's good enough for me. (Seriously, Wickleder et al. call it "the largest potential for thorium", and this in a review of thorium chemistry instead of a glowing pro-thorium-power pamphlet.) I think it makes more sense to put in applications that may be on the rise first, before those that are on the wane. Today, thorium tends to be used only when its radioactivity is needed. Double sharp (talk) 08:24, 1 August 2016 (UTC)[reply]

I can not look into the future and I doubt that Greenwood and Wickleder can do. Thorium-based_nuclear_power#Current_projects#India clearly states that it is not running. This is a Prototype which makes it a lab test equipmemnt but not a seriuos use. I can not see any serious efford to make this a large scale use. __Stone (talk) 20:57, 1 August 2016 (UTC)[reply]

Under "Nuclear reactors and atomic energy" (under applications) Greenwood starts by covering ²³⁵U and its long history, and then mentions ²³³U and ²³⁹Pu under the same section, writing about the advantages of ²³³U and then mentioning the reprocessing problems because of the energetic gamma decay of the daughters. (Yes, he also writes a whole paragraph about the prototype breeder reactors for ²³⁹Pu, also as an application.) Further, Wickleder is very positive about the whole thing, listing it after the non-nuclear applications: "Maybe the largest potential for thorium is its use in nuclear energy." And after listing advantages and disadvantages he writes "The nuclear technology has nevertheless matured with the development of high-temperature gas-cooled reactors". Also, the Indian official programme looks like a very serious, governmental effort to make Th reactors happen (along with the reactor at Kalpakkam, which uses some ²³³U as well as ²³⁵U and ²³⁹Pu). Double sharp (talk) 06:57, 2 August 2016 (UTC)[reply]

The Chinese will start the reactor in the 2030s and the Indians have not yet selected a building site according to the USGS comodity report. To make the future for thorium what it is proposed by the crystall ball fraction a lot of things have to happen in the future. Best would be a section on nuclear fuel, but with much less enthusiasm and kill it completely from the use section, because it is not a use it is a future use. --Stone (talk) 20:51, 3 August 2016 (UTC)[reply]

The new organization in the text is really looking great!--Stone (talk) 20:47, 17 August 2016 (UTC)[reply]

• "The main advantage of the thorium fuel cycle is that thorium is more abundant than uranium and hence can satisfy world energy demands for longer." (warning: I'm poorly familiar with the nuclear technology) you surely don't mean people are going to mine all uranium or thorium so relative abundance becomes relevant? I'd think what is more relevant is easiness of extraction of the elements from mines and mining itself
• "not only does 233U have a higher probability of fission upon neutron capture than 235U" for the record, what quantities are we talking about? Probably suitable for a note
• "(n,2n) reactions" I understand it, but this is somewhat hardcore. Maybe if you rewrite the reaction chain in this notation, it becomes easier to get on with (the chain would also be technically more accurate). By the way, do you actually need that chain?
• you mention the advantages, then you mention the disadvantages, and then it suddenly turns out there are more advantages and disadvantages! Restructure this.
• Also, commercial viability deserves its own discussion, it's not just another disadvantage. Why is it not viable, by the way?
• "In 1997, the U.S. Energy Department underwrote research into thorium fuel" this whole discussion belongs to History
• "other companies: Raytheon Nuclear Inc., Brookhaven National Laboratory and the Kurchatov Institute in Moscow." Why is location given only for one institute? Why are they all referred to as companies?
• The story is a little weak here if you look closely: the U.S. considered an idea and an Isreali scientist formed a coalition. Tgis could be the case, but this deserves an explanation
• "USA's" it is advised not to use the three-letter acronym in Wiki for whatever reason per MOS
• "with the goal of achieving energy independence" who is India dependent on with energy? Really interested
• Stone said the Chinese will launch their first site in the 2030s. Would be nice to mention that here. Who has any plans aside from China and India?

The section is more or less good on the technical part.--

• But there's an issue I forgot to mention. That wikitexted graph. First of all, it has increase of Z doing down rather than the usual up, but that's the least of my concerns (though please change that too). What do the colors mean? I know what the fact there is a color means, but what do different colors mean? Wouldn't it be better to ask the Graphics Lab to make a svg graph with a legend and beauty and stuff?--
  talk) 19:56, 8 August 2016 (UTC)[reply
  ]
  • Different colours refer to different orders of magnitude of half-lives, but I am not entirely sure if it matters enough that it should be mentioned. I think part of the motivation for Z increasing going down is to show the fission of ²³²U, ²³³U, and ²³⁵U, but actually I think what I would do is to touch up a chart of nuclides with arrows and give the three fissile uranium nuclides there a red border or something. Double sharp (talk) 12:15, 17 August 2016 (UTC)[reply]

Precautions

• "As thorium occurs naturally, it exists in very small quantities almost everywhere on Earth: the average human contains about 100 micrograms of thorium and typically consumes three micrograms per day of thorium.[130]" nice start! (no action required)
• "This exposure is raised for people who ..." nice continuation! (again, no action required)
• "exposure to an aerosol of thorium" how could that happen?
  • Contaminated dust, perhaps? Added. Double sharp (talk) 16:42, 3 September 2016 (UTC)[reply]
• "As a result, owning and handling small amounts of thorium, such as a gas mantle, is considered safe. [...] There are concerns about the safety of thorium mantles" uhmm?
  • I think the idea is that everyone agrees that a thorium gas mantle is perfectly safe as long as you don't use it. The source says "gas lantern mantles...generally do not pose serious health risks, but may nevertheless be retired from use as a prudent avoidance measure." The problem is that it is perfectly safe as long as it sits there because the thorium and its daughters can't get into you, but upon use everything is volatilised and suddenly they can. Clarified. Double sharp (talk) 16:42, 3 September 2016 (UTC)[reply]
• "If a mantle is ingested" how could that happen? like really, how?--
  talk) 20:10, 8 August 2016 (UTC)[reply
  ]
  • This was in the source. I could imagine young children trying it. The source cited explicitly notes this. Alas, I have found that it is a rather futile quest to drink to the dregs the bottomless cups of human stupidity. Double sharp (talk) 16:42, 3 September 2016 (UTC)[reply]
• Is anything known on how thorium's chemistry harms the body?
  • I tried researching on this, but found nothing. If it's anywhere, it must be in Gmelin somewhere. Presumably the reason is that the radioactivity drowns it out, unlike for uranium when you really have to take both chemical and radiological toxicity into account. In fact, the one study I found about this compared thorium with uranium and neptunium (because ²³⁸U and ²³⁷Np are the most common isotopes and are long-lived enough to not cause problems; ²⁴⁴Pu and ²⁴⁷Cm can't be produced in enough quantities). It showed that thorium was actually chemically rather non-toxic to cells, whereas uranium and neptunium induced apoptosis. It might have psychological effects, judging from [www.omicsonline.org/occupational-thorium-exposure-or-self-poisoning-2161-0494.S5-002.php?aid=5345^{[predatory publisher]} this study], but this patient's paranoia may have predated his minuscule thorium exposure. Double sharp (talk) 16:42, 3 September 2016 (UTC)[reply]
• "The burning of thorium metal powder sludge resulted in the 1956 Sylvania Electric Products explosion, which resulted in nine injuries, some severe, as well as one death from thorium poisoning.[139][140][141]" the sentence is poorly worded: it puts the stress on the explosion and not on those injured and dead.--
  talk) 20:10, 8 August 2016 (UTC)[reply
  ]
  • Tried to fix this. Double sharp (talk) 16:42, 3 September 2016 (UTC)[reply]

Notes

I succeeded in cutting the notes down from the ridiculous 26 there used to be to 10. ^_^ Double sharp (talk) 13:29, 23 July 2016 (UTC)[reply]

Ten is a very decent number. Looks like many (and the article looks well-researched) but not too many (and the impression isn't ruined). I think I'd put ten or twelve as the upper limit.--

talk) 16:25, 23 July 2016 (UTC)[reply

]

• Can we get a picture of a big chunk of Th for Bulkproperties, even if in poor quality?
  • We used to have one, but it got deleted as it wasn't a free picture. It is actually annoyingly difficult to get large chunks of thorium metal. This is because the usual amounts of lead shielding that work perfectly fine for uranium metal are insufficient, because the particles emitted by the decaying daughters of thorium are too high in energy. Double sharp (talk) 05:18, 10 August 2016 (UTC)[reply]
• any pic of that Th aqueous ion would be better than the uncalled for pic of ThO2 with oxygen being fluorine-colored. Are any photos of actual compounds available?
• can we get a pic of a burning mantle?
• a thorium production plant?
• a thorium-based reactor (a model will work)

--

I re-read

talk) 17:11, 9 August 2016 (UTC)[reply

]

• Why was Th phased out only in the nineties?
  • I finally found the reason: because it was only then that adequate substitutes were found. Previously thorium was thought to be indispensable, for example for getting the really bright light from the mantles, until it was noticed that yttrium was almost as good for this purpose, and similarly alternatives were found for the other applications. (Th is still usually the best, but the competitors are now known to be close enough that the benefits of Th are outweighed by the dangers of radioactivity – mostly not from Th, but its murderous daughters.) Double sharp (talk) 15:05, 23 July 2016 (UTC)[reply]
    • Wow. Thank you for finding this out. One last question: was thorium used before substitutes were found labeled as/considered to any extent dangerous in the practical sense? For example, americium in smoke detecors isn't considered dangerous because there's so little of it there IIRC.
      • Yes, in practice there are some dangers. I'll use the old thorium mantles as the main example here, since it was always among the largest uses and has the most problems (which are still made and sold by some companies, who tend to avoid mentioning radioactivity whenever possible, which is somewhat dubious from a safety or legal point of view). There is the radiation dose you get every time you use it, because while the Th is fine, the Ra is volatilised and you can easily breathe it in. Apart from that, the main danger is not to users (provided they use it properly), but rather to the factory workers and the environmental damage they cause in landfills, because while the radiation from one mantle is not so bad, that from the large number of mantles gathered together at the factory or the landfill is quite a big problem. This (which I added) was certainly known by the 1980s, as that's when the sources I added came from. In the case of thorium as a contrast medium, the dangers were already known by the 1950s, and the switch was faster because there was an alternative. (It was used a lot in the 1930s and 1940s because there was no good alternative yet.) Double sharp (talk) 16:43, 23 July 2016 (UTC)[reply]
        • Thank you. I'll look in a few hours how I would want to accommodate this into the text, but in general, such facts and research are FA-worthy, very interesting to learn.--
          talk) 16:55, 23 July 2016 (UTC)[reply
          ]

• Find a reason why ²³⁰Th occurs in seawaters
  • It's always around (see the infobox which lists the isotopic composition as 99.98% ²³²Th and 0.02% ²³⁰Th); it's just easier to detect in seawaters, because while ²³²Th would sit at the bottom, you get to see ²³⁰Th precipitate out and sink down as it is the daughter of soluble ²³⁴U. Actually, wasn't this already in Isotopes? Double sharp (talk) 11:56, 22 July 2016 (UTC)[reply]
    • Yes, right, I forgot this had been fixed.--
      talk) 12:08, 22 July 2016 (UTC)[reply
      ]

• Add a para with stats to Formation (see, for example, last para in Lead#In space)

Why is thorium so stable? I admit, I did try to answer this question. After Pb completes a proton shell at Z=82, the next subshell to be filled is according to this site 1h_9/2, which gets us to Z=92. Which explains uranium nicely, but not thorium. Perversely, if you look at the neutron subshells after N=126, 2g_9/2 gets us to N=136 and then 3d_5/2 to N=142, which explains thorium nicely, but not uranium. Then again, since actinide nuclei are not spherical, we should not expect these predictions to be sensible in the first place. This may not actually be explainable in an understandable manner for the actinides. (I dare to say this sort of thing for the spherical early lanthanide nuclei; see the discussion I wrote for cerium, for which this is actually a reason why it is so common. But for nuclei with 150 < A < 190 and A > 220, the shell model simply does not apply, even in the vicinity of the line of beta stability, because these nuclei are not spherical.) Double sharp (talk) 10:30, 26 July 2016 (UTC)[reply]

• Get back to Production after it's basically reformed

• Write to that Dutch company that employed the two guys from 1914 whose names we cannot find

• Thorium energy in the 21st century?

• Why do we need more than a sentence for radiodating? It's easy to explain, but is that needed?

N

• Evolution of Earth's radiogenic heat.svg implies that Th-232 is the major source of internal heat of Earth at the moment. If that is correct, it should be spelled out in the text.
  Nergaal (talk) 15:34, 11 October 2016 (UTC)[reply
  ]
  • I would not dare to say it is the "major" source, as to me that implies that it accounts for most of it, when actually ²³⁸U is not really far behind. Double sharp (talk) 14:16, 7 November 2016 (UTC)[reply]
    • It is still the largest/predominant one. My impression was that U is THE source of internal heat, but it appears that Th is the largest. I am assuming most that know of this subject would also think U is the largest, so I think it is important to be clear and specific about Th and how much it does.
      Nergaal (talk) 10:05, 12 November 2016 (UTC)[reply
      ]
      • @
        Nergaal: I took a stab at this in the article; calling it the "largest single contributor" I think correctly implies that it's a plurality but not a majority. 71.41.210.146 (talk) 20:22, 1 January 2017 (UTC)[reply
        ]
• Text doesnt need lattice parameters, and density doesn't need more than 3 sig figs.
  Nergaal (talk) 18:10, 1 November 2016 (UTC)[reply
  ]
  •  Done Double sharp (talk) 14:16, 7 November 2016 (UTC)[reply]
• It's unclear what does File:PSM V74 D233 Thorium radioactive incandescent gas mantle placed above plant seeds.png represent.
  Nergaal (talk) 18:10, 1 November 2016 (UTC)[reply
  ]

Continued at Talk:Thorium/PR continued with R8R. Double sharp (talk) 01:30, 12 May 2017 (UTC)[reply]