Seaborgium
Seaborgium | |||||||||||||||||||||||||||||||||||||||||||||
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Pronunciation | /siːˈbɔːrɡiəm/ ⓘ | ||||||||||||||||||||||||||||||||||||||||||||
Mass number | [269] | ||||||||||||||||||||||||||||||||||||||||||||
Seaborgium in the periodic table | |||||||||||||||||||||||||||||||||||||||||||||
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Discovery | Lawrence Berkeley National Laboratory (1974) | ||||||||||||||||||||||||||||||||||||||||||||
Isotopes of seaborgium | |||||||||||||||||||||||||||||||||||||||||||||
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Seaborgium is a
In the
In 1974, a few atoms of seaborgium were produced in laboratories in the Soviet Union and in the United States. The priority of the discovery and therefore the naming of the element was disputed between Soviet and American scientists, and it was not until 1997 that the International Union of Pure and Applied Chemistry (IUPAC) established seaborgium as the official name for the element. It is one of only two elements named after a living person at the time of naming, the other being oganesson, element 118.[a]
Introduction
Synthesis of superheavy nuclei
A superheavy[b] atomic nucleus is created in a nuclear reaction that combines two other nuclei of unequal size[c] into one; roughly, the more unequal the two nuclei in terms of mass, the greater the possibility that the two react.[17] The material made of the heavier nuclei is made into a target, which is then bombarded by the beam of lighter nuclei. Two nuclei can only fuse into one if they approach each other closely enough; normally, nuclei (all positively charged) repel each other due to electrostatic repulsion. The strong interaction can overcome this repulsion but only within a very short distance from a nucleus; beam nuclei are thus greatly accelerated in order to make such repulsion insignificant compared to the velocity of the beam nucleus.[18] The energy applied to the beam nuclei to accelerate them can cause them to reach speeds as high as one-tenth of the speed of light. However, if too much energy is applied, the beam nucleus can fall apart.[18]
Coming close enough alone is not enough for two nuclei to fuse: when two nuclei approach each other, they usually remain together for approximately 10−20 seconds and then part ways (not necessarily in the same composition as before the reaction) rather than form a single nucleus.[18][19] This happens because during the attempted formation of a single nucleus, electrostatic repulsion tears apart the nucleus that is being formed.[18] Each pair of a target and a beam is characterized by its cross section—the probability that fusion will occur if two nuclei approach one another expressed in terms of the transverse area that the incident particle must hit in order for the fusion to occur.[d] This fusion may occur as a result of the quantum effect in which nuclei can tunnel through electrostatic repulsion. If the two nuclei can stay close for past that phase, multiple nuclear interactions result in redistribution of energy and an energy equilibrium.[18]
External videos | |
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Visualization of unsuccessful nuclear fusion, based on calculations from the Australian National University[21] |
The resulting merger is an excited state[22]—termed a compound nucleus—and thus it is very unstable.[18] To reach a more stable state, the temporary merger may fission without formation of a more stable nucleus.[23] Alternatively, the compound nucleus may eject a few neutrons, which would carry away the excitation energy; if the latter is not sufficient for a neutron expulsion, the merger would produce a gamma ray. This happens in approximately 10−16 seconds after the initial nuclear collision and results in creation of a more stable nucleus.[23] The definition by the IUPAC/IUPAP Joint Working Party (JWP) states that a chemical element can only be recognized as discovered if a nucleus of it has not decayed within 10−14 seconds. This value was chosen as an estimate of how long it takes a nucleus to acquire its outer electrons and thus display its chemical properties.[24][e]
Decay and detection
The beam passes through the target and reaches the next chamber, the separator; if a new nucleus is produced, it is carried with this beam.[26] In the separator, the newly produced nucleus is separated from other nuclides (that of the original beam and any other reaction products)[f] and transferred to a surface-barrier detector, which stops the nucleus. The exact location of the upcoming impact on the detector is marked; also marked are its energy and the time of the arrival.[26] The transfer takes about 10−6 seconds; in order to be detected, the nucleus must survive this long.[29] The nucleus is recorded again once its decay is registered, and the location, the energy, and the time of the decay are measured.[26]
Stability of a nucleus is provided by the strong interaction. However, its range is very short; as nuclei become larger, its influence on the outermost nucleons (protons and neutrons) weakens. At the same time, the nucleus is torn apart by electrostatic repulsion between protons, and its range is not limited.[30] Total binding energy provided by the strong interaction increases linearly with the number of nucleons, whereas electrostatic repulsion increases with the square of the atomic number, i.e. the latter grows faster and becomes increasingly important for heavy and superheavy nuclei.[31][32] Superheavy nuclei are thus theoretically predicted[33] and have so far been observed[34] to predominantly decay via decay modes that are caused by such repulsion: alpha decay and spontaneous fission.[g] Almost all alpha emitters have over 210 nucleons,[36] and the lightest nuclide primarily undergoing spontaneous fission has 238.[37] In both decay modes, nuclei are inhibited from decaying by corresponding energy barriers for each mode, but they can be tunnelled through.[31][32]
Alpha particles are commonly produced in radioactive decays because mass of an alpha particle per nucleon is small enough to leave some energy for the alpha particle to be used as kinetic energy to leave the nucleus.
Alpha decays are registered by the emitted alpha particles, and the decay products are easy to determine before the actual decay; if such a decay or a series of consecutive decays produces a known nucleus, the original product of a reaction can be easily determined.[i] (That all decays within a decay chain were indeed related to each other is established by the location of these decays, which must be in the same place.)[26] The known nucleus can be recognized by the specific characteristics of decay it undergoes such as decay energy (or more specifically, the kinetic energy of the emitted particle).[j] Spontaneous fission, however, produces various nuclei as products, so the original nuclide cannot be determined from its daughters.[k]
The information available to physicists aiming to synthesize a superheavy element is thus the information collected at the detectors: location, energy, and time of arrival of a particle to the detector, and those of its decay. The physicists analyze this data and seek to conclude that it was indeed caused by a new element and could not have been caused by a different nuclide than the one claimed. Often, provided data is insufficient for a conclusion that a new element was definitely created and there is no other explanation for the observed effects; errors in interpreting data have been made.[l]History
Following claims of the observation of elements 104 and 105 in 1970 by Albert Ghiorso et al. at the Lawrence Livermore National Laboratory, a search for element 106 using oxygen-18 projectiles and the previously used californium-249 target was conducted.[55] Several 9.1 MeV alpha decays were reported and are now thought to originate from element 106, though this was not confirmed at the time. In 1972, the HILAC accelerator received equipment upgrades, preventing the team from repeating the experiment, and data analysis was not done during the shutdown.[55] This reaction was tried again several years later, in 1974, and the Berkeley team realized that their new data agreed with their 1971 data, to the astonishment of Ghiorso. Hence, element 106 could have actually been discovered in 1971 if the original data was analyzed more carefully.[55]
Two groups claimed
- 207+ 54
82Pb
24Cr
→ 260
106Sg
+
n
A few months later in 1974, researchers including Glenn T. Seaborg,
A dispute thus arose from the initial competing claims of discovery, though unlike the case of the synthetic elements up to
Seaborg had previously suggested to the TWG that if Berkeley was recognised as the official discoverer of elements 104 and 105, they might propose the name kurchatovium (symbol Kt) for element 106 to honour the Dubna team, which had proposed this name for element 104 after
...we were given credit for the discovery and the accompanying right to name the new element. The eight members of the Ghiorso group suggested a wide range of names honoring Isaac Newton, Thomas Edison, Leonardo da Vinci, Ferdinand Magellan, the mythical Ulysses, George Washington, and Finland, the native land of a member of the team. There was no focus and no front-runner for a long period.
Then one day Al [Ghiorso] walked into my office and asked what I thought of naming element 106 "seaborgium." I was floored.[59]— Glenn Seaborg
Seaborg's son Eric remembered the naming process as follows:[60]
With eight scientists involved in the discovery suggesting so many good possibilities, Ghiorso despaired of reaching consensus, until he awoke one night with an idea. He approached the team members one by one, until seven of them had agreed. He then told his friend and colleague of 50 years: "We have seven votes in favor of naming element 106 seaborgium. Will you give your consent?" My father was flabbergasted, and, after consulting my mother, agreed.[60]
— Eric Seaborg
The name seaborgium and symbol Sg were announced at the 207th national meeting of the
Atomic number | Systematic | American | Russian | German | Compromise 92 | IUPAC 94 | ACS 94 | IUPAC 95 | IUPAC 97 | Present |
---|---|---|---|---|---|---|---|---|---|---|
101 | unnilunium | mendelevium | — | — | mendelevium | mendelevium | mendelevium | mendelevium | mendelevium | mendelevium |
102 | unnilbium | nobelium | joliotium | — | joliotium | nobelium | nobelium | flerovium | nobelium | nobelium |
103 | unniltrium | lawrencium | rutherfordium | — | lawrencium | lawrencium | lawrencium | lawrencium | lawrencium | lawrencium |
104 | unnilquadium | rutherfordium | kurchatovium | — | meitnerium | dubnium | rutherfordium | dubnium | rutherfordium | rutherfordium |
105 | unnilpentium | hahnium | nielsbohrium | — | kurchatovium | joliotium | hahnium | joliotium | dubnium | dubnium |
106 | unnilhexium | seaborgium | — | — | rutherfordium | rutherfordium | seaborgium | seaborgium | seaborgium | seaborgium |
107 | unnilseptium | — | — | nielsbohrium | nielsbohrium | bohrium | nielsbohrium | nielsbohrium | bohrium | bohrium |
108 | unniloctium | — | — | hassium | hassium | hahnium | hassium | hahnium | hassium | hassium |
109 | unnilennium | — | — | meitnerium | hahnium | meitnerium | meitnerium | meitnerium | meitnerium | meitnerium |
110 | ununnilium | hahnium | becquerelium | darmstadtium | — | — | — | — | — | darmstadtium |
111 | unununium | — | — | roentgenium | — | — | — | — | — | roentgenium |
112 | ununbium | — | — | copernicium | — | — | — | — | — | copernicium |
This decision ignited a firestorm of worldwide protest for disregarding the historic discoverer's right to name new elements, and against the new retroactive rule against naming elements after living persons; the American Chemical Society stood firmly behind the name seaborgium for element 106, together with all the other American and German naming proposals for elements 104 to 109, approving these names for its journals in defiance of IUPAC.[58] At first, IUPAC defended itself, with an American member of its committee writing: "Discoverers don't have a right to name an element. They have a right to suggest a name. And, of course, we didn't infringe on that at all." However, Seaborg responded:
This would be the first time in history that the acknowledged and uncontested discoverers of an element are denied the privilege of naming it.[59]
— Glenn Seaborg
Bowing to public pressure, IUPAC proposed a different compromise in August 1995, in which the name seaborgium was reinstated for element 106 in exchange for the removal of all but one of the other American proposals, which met an even worse response. Finally, IUPAC rescinded these previous compromises and made a final, new recommendation in August 1997, in which the American and German proposals for elements 104 to 109 were all adopted, including seaborgium for element 106, with the single exception of element 105, named dubnium to recognise the contributions of the Dubna team to the experimental procedures of transactinide synthesis. This list was finally accepted by the American Chemical Society, which wrote:[58]
In the interest of international harmony, the Committee reluctantly accepted the name 'dubnium' for element 105 in place of 'hahnium' [the American proposal], which has had long-standing use in literature. We are pleased to note that 'seaborgium' is now the internationally approved name for element 106.[58]
— American Chemical Society
Seaborg commented regarding the naming:
I am, needless to say, proud that U.S. chemists recommended that element 106, which is placed under tungsten (74), be called 'seaborgium.' I was looking forward to the day when chemical investigators will refer to such compounds as seaborgous chloride, seaborgic nitrate, and perhaps, sodium seaborgate.
This is the greatest honor ever bestowed upon me—even better, I think, than winning the Nobel Prize.[m] Future students of chemistry, in learning about the periodic table, may have reason to ask why the element was named for me, and thereby learn more about my work.[59]— Glenn Seaborg
Seaborg died a year and a half later, on 25 February 1999, at the age of 86.[59]
Isotopes
Isotope | Half-life[n] | Decay mode |
Discovery year |
Discovery reaction | |
---|---|---|---|---|---|
Value | ref | ||||
258Sg | 2.7 ms | [7] | SF | 1994 | 209Bi(51V,2n) |
259Sg | 402 ms | [7] | α | 1985 | 207Pb(54Cr,2n) |
259mSg | 226 ms | [7] | α, SF | 2015 | 206Pb(54Cr,n)[62] |
260Sg | 4.95 ms | [7] | SF, α | 1985 | 208Pb(54Cr,2n) |
261Sg | 183 ms | [7] | α, β+, SF | 1985 | 208Pb(54Cr,n) |
261mSg | 9.3 μs | [7] | IT | 2009 | 208Pb(54Cr,n) |
262Sg | 10.3 ms | [7] | SF, α | 2001 | 270Ds(—,2α) |
263Sg | 940 ms | [7] | α, SF | 1994 | 271Ds(—,2α) |
263mSg | 420 ms | [7] | α | 1974 | 249Cf(18O,4n) |
264Sg | 78 ms | [7] | SF | 2006 | 238U(34Si,4n) |
265Sg | 9.2 s | [7] | α | 1993 | 248Cm(22Ne,5n) |
265mSg | 16.4 s | [7] | α | 1993 | 248Cm(22Ne,5n) |
266Sg | 390 ms | [7] | SF | 2004 | 270Hs(—,α) |
267Sg | 1.8 min | [7] | SF, α | 2004 | 271Hs(—,α) |
268Sg | 13 s | [8] | SF | 2022 | 276Ds(—,2α) |
269Sg | 14 min | [9] | α | 2010 | 285Fl(—,4α) |
271Sg | 31 s | [10] | α, SF | 2003 | 287Fl(—,4α) |
Depending on the energies involved, fusion reactions that generate superheavy elements are separated into "hot" and "cold". In hot fusion reactions, very light, high-energy projectiles are accelerated toward very heavy targets (actinides), giving rise to compound nuclei at high excitation energy (~40–50 MeV) that may either fission or evaporate several (3 to 5) neutrons.[63] In cold fusion reactions, the produced fused nuclei have a relatively low excitation energy (~10–20 MeV), which decreases the probability that these products will undergo fission reactions. As the fused nuclei cool to the ground state, they require emission of only one or two neutrons, and thus, allows for the generation of more neutron-rich products.[64] The latter is a distinct concept from that of where nuclear fusion claimed to be achieved at room temperature conditions (see cold fusion).[65]
Seaborgium has no stable or naturally occurring isotopes. Several radioactive isotopes have been synthesized in the laboratory, either by fusing two atoms or by observing the decay of heavier elements. Thirteen different isotopes of seaborgium have been reported with mass numbers 258–269 and 271, three of which, seaborgium-261, 263, and 265, have known
There is a trend toward increasing half-lives for the heavier isotopes, though
The proton-rich isotopes from 258Sg to 261Sg were directly produced by cold fusion; all heavier isotopes were produced from the repeated alpha decay of the heavier elements hassium, darmstadtium, and flerovium, with the exceptions of the isotopes 263mSg, 264Sg, 265Sg, and 265mSg, which were directly produced by hot fusion through irradiation of actinide targets. The twelve isotopes of seaborgium have half-lives ranging from 92 microseconds for 261mSg to 14 minutes for 269Sg.[9][66]
Predicted properties
Very few properties of seaborgium or its compounds have been measured; this is due to its extremely limited and expensive production[68] and the fact that seaborgium (and its parents) decays very quickly. A few singular chemistry-related properties have been measured, but properties of seaborgium metal remain unknown and only predictions are available.
Physical
Seaborgium is expected to be a solid under normal conditions and assume a
Chemical
Seaborgium is the fourth member of the 6d series of transition metals and the heaviest member of group 6 in the periodic table, below chromium, molybdenum, and tungsten. All the members of the group form a diversity of oxoanions. They readily portray their group oxidation state of +6, although this is highly oxidising in the case of chromium, and this state becomes more and more stable to reduction as the group is descended: indeed, tungsten is the last of the 5d transition metals where all four 5d electrons participate in metallic bonding.[69] As such, seaborgium should have +6 as its most stable oxidation state, both in the gas phase and in aqueous solution, and this is the only positive oxidation state that is experimentally known for it; the +5 and +4 states should be less stable, and the +3 state, the most common for chromium, would be the least stable for seaborgium.[1]
This stabilisation of the highest oxidation state occurs in the early 6d elements because of the similarity between the energies of the 6d and 7s orbitals, since the 7s orbitals are relativistically stabilised and the 6d orbitals are relativistically destabilised. This effect is so large in the seventh period that seaborgium is expected to lose its 6d electrons before its 7s electrons (Sg, [Rn]5f146d47s2; Sg+, [Rn]5f146d37s2; Sg2+, [Rn]5f146d37s1; Sg4+, [Rn]5f146d2; Sg6+, [Rn]5f14). Because of the great destabilisation of the 7s orbital, SgIV should be even more unstable than WIV and should be very readily oxidised to SgVI. The predicted ionic radius of the hexacoordinate Sg6+ ion is 65 pm, while the predicted atomic radius of seaborgium is 128 pm. Nevertheless, the stability of the highest oxidation state is still expected to decrease as LrIII > RfIV > DbV > SgVI. Some predicted
2 SgO3 + 2 H+ + 2 e− ⇌ Sg2O5 + H2O E0 = −0.046 V Sg2O5 + 2 H+ + 2 e− ⇌ 2 SgO2 + H2O E0 = +0.11 V SgO2 + 4 H+ + e− ⇌ Sg3+ + 2 H2O E0 = −1.34 V Sg3+ + e− ⇌ Sg2+ E0 = −0.11 V Sg3+ + 3 e− ⇌ Sg E0 = +0.27 V
Seaborgium should form a very volatile
Molybdenum and tungsten are very similar to each other and show important differences to the smaller chromium, and seaborgium is expected to follow the chemistry of tungsten and molybdenum quite closely, forming an even greater variety of oxoanions, the simplest among them being seaborgate, SgO2−
4, which would form from the rapid hydrolysis of Sg(H
2O)6+
6, although this would take place less readily than with molybdenum and tungsten as expected from seaborgium's greater size. Seaborgium should hydrolyse less readily than tungsten in hydrofluoric acid at low concentrations, but more readily at high concentrations, also forming complexes such as SgO3F− and SgOF−
5: complex formation competes with hydrolysis in hydrofluoric acid.[1]
Experimental chemistry
Experimental chemical investigation of seaborgium has been hampered due to the need to produce it one atom at a time, its short half-life, and the resulting necessary harshness of the experimental conditions.[71] The isotope 265Sg and its isomer 265mSg are advantageous for radiochemistry: they are produced in the 248Cm(22Ne,5n) reaction.[72]
In the first experimental chemical studies of seaborgium in 1995 and 1996, seaborgium atoms were produced in the reaction 248Cm(22Ne,4n)266Sg, thermalised, and reacted with an O2/HCl mixture. The adsorption properties of the resulting oxychloride were measured and compared with those of molybdenum and tungsten compounds. The results indicated that seaborgium formed a volatile oxychloride akin to those of the other group 6 elements, and confirmed the decreasing trend of oxychloride volatility down group 6:
- Sg + O
2 + 2 HCl → SgO
2Cl
2 + H
2
In 2001, a team continued the study of the gas phase chemistry of seaborgium by reacting the element with O2 in a H2O environment. In a manner similar to the formation of the oxychloride, the results of the experiment indicated the formation of seaborgium oxide hydroxide, a reaction well known among the lighter group 6 homologues as well as the pseudohomologue uranium.[73]
- 2 Sg + 3 O
2 → 2 SgO
3 - SgO
3 + H
2O → SgO
2(OH)
2
Predictions on the aqueous chemistry of seaborgium have largely been confirmed. In experiments conducted in 1997 and 1998, seaborgium was eluted from cation-exchange resin using a HNO3/HF solution, most likely as neutral SgO2F2 or the anionic complex ion [SgO2F3]− rather than SgO2−
4. In contrast, in 0.1 M nitric acid, seaborgium does not elute, unlike molybdenum and tungsten, indicating that the hydrolysis of [Sg(H2O)6]6+ only proceeds as far as the cationic complex [Sg(OH)4(H2O)]2+ or [SgO(OH)3(H2O)2]+, while that of molybdenum and tungsten proceed to neutral [MO2(OH)2].[1]
The only other oxidation state known for seaborgium other than the group oxidation state of +6 is the zero oxidation state. Similarly to its three lighter congeners, forming chromium hexacarbonyl, molybdenum hexacarbonyl, and tungsten hexacarbonyl, seaborgium has been shown in 2014 to also form seaborgium hexacarbonyl, Sg(CO)6. Like its molybdenum and tungsten homologues, seaborgium hexacarbonyl is a volatile compound that reacts readily with silicon dioxide.[71]
Absence in nature
Searches for long-lived primordial nuclides of seaborgium in nature have all yielded negative results. One 2022 study estimated the concentration of seaborgium atoms in natural tungsten (its chemical homolog) is less than 5.1×10−15 atom(Sg)/atom(W).[74]
Notes
- ^ The names einsteinium and fermium for elements 99 and 100 were proposed when their namesakes (Albert Einstein and Enrico Fermi respectively) were still alive, but were not made official until Einstein and Fermi had died.[11]
- superactinide series).[14]Terms "heavy isotopes" (of a given element) and "heavy nuclei" mean what could be understood in the common language—isotopes of high mass (for the given element) and nuclei of high mass, respectively.
- ^ The amount of energy applied to the beam particle to accelerate it can also influence the value of cross section. For example, in the 28
14Si
+ 1
0n
→ 28
13Al
+ 1
1p
reaction, cross section changes smoothly from 370 mb at 12.3 MeV to 160 mb at 18.3 MeV, with a broad peak at 13.5 MeV with the maximum value of 380 mb.[20] - ^ This figure also marks the generally accepted upper limit for lifetime of a compound nucleus.[25]
- ^ This separation is based on that the resulting nuclei move past the target more slowly then the unreacted beam nuclei. The separator contains electric and magnetic fields whose effects on a moving particle cancel out for a specific velocity of a particle.[27] Such separation can also be aided by a time-of-flight measurement and a recoil energy measurement; a combination of the two may allow to estimate the mass of a nucleus.[28]
- ^ Not all decay modes are caused by electrostatic repulsion. For example, beta decay is caused by the weak interaction.[35]
- ^ It was already known by the 1960s that ground states of nuclei differed in energy and shape as well as that certain magic numbers of nucleons corresponded to greater stability of a nucleus. However, it was assumed that there was no nuclear structure in superheavy nuclei as they were too deformed to form one.[40]
- ^ Since mass of a nucleus is not measured directly but is rather calculated from that of another nucleus, such measurement is called indirect. Direct measurements are also possible, but for the most part they have remained unavailable for superheavy nuclei.[45] The first direct measurement of mass of a superheavy nucleus was reported in 2018 at LBNL.[46] Mass was determined from the location of a nucleus after the transfer (the location helps determine its trajectory, which is linked to the mass-to-charge ratio of the nucleus, since the transfer was done in presence of a magnet).[47]
- ^ If the decay occurred in a vacuum, then since total momentum of an isolated system before and after the decay must be preserved, the daughter nucleus would also receive a small velocity. The ratio of the two velocities, and accordingly the ratio of the kinetic energies, would thus be inverse to the ratio of the two masses. The decay energy equals the sum of the known kinetic energy of the alpha particle and that of the daughter nucleus (an exact fraction of the former).[36] The calculations hold for an experiment as well, but the difference is that the nucleus does not move after the decay because it is tied to the detector.
- Georgy Flerov,[48] a leading scientist at JINR, and thus it was a "hobbyhorse" for the facility.[49] In contrast, the LBL scientists believed fission information was not sufficient for a claim of synthesis of an element. They believed spontaneous fission had not been studied enough to use it for identification of a new element, since there was a difficulty of establishing that a compound nucleus had only ejected neutrons and not charged particles like protons or alpha particles.[25] They thus preferred to link new isotopes to the already known ones by successive alpha decays.[48]
- ^ For instance, element 102 was mistakenly identified in 1957 at the Nobel Institute of Physics in Stockholm, Stockholm County, Sweden.[50] There were no earlier definitive claims of creation of this element, and the element was assigned a name by its Swedish, American, and British discoverers, nobelium. It was later shown that the identification was incorrect.[51] The following year, RL was unable to reproduce the Swedish results and announced instead their synthesis of the element; that claim was also disproved later.[51] JINR insisted that they were the first to create the element and suggested a name of their own for the new element, joliotium;[52] the Soviet name was also not accepted (JINR later referred to the naming of the element 102 as "hasty").[53] This name was proposed to IUPAC in a written response to their ruling on priority of discovery claims of elements, signed 29 September 1992.[53] The name "nobelium" remained unchanged on account of its widespread usage.[54]
- ^ Seaborg had in fact previously won the 1951 Nobel Prize in Chemistry together with Edwin McMillan for "their discoveries in the chemistry of the first transuranium elements".[61]
- ^ Different sources give different values for half-lives; the most recently published values are listed.
References
- ^ ISBN 1-4020-3555-1.
- ^ .
- ^ .
- ^ a b Kratz; Lieser (2013). Nuclear and Radiochemistry: Fundamentals and Applications (3rd ed.). p. 631.
- ^ ISBN 978-3-540-07109-9. Retrieved 4 October 2013.
- ^ "Periodic Table, Seaborgium". Royal Chemical Society. Retrieved 20 February 2017.
- ^ .
- ^ .
- ^ .
- ^ S2CID 251759318.
- ^ Hoffman, Ghiorso & Seaborg 2000, pp. 187–189.
- ^ Krämer, K. (2016). "Explainer: superheavy elements". Chemistry World. Retrieved 2020-03-15.
- ^ "Discovery of Elements 113 and 115". Lawrence Livermore National Laboratory. Archived from the original on 2015-09-11. Retrieved 2020-03-15.
- S2CID 127060181.
- ISSN 0556-2813.
- S2CID 123288075. Archived from the original(PDF) on 7 June 2015. Retrieved 20 October 2012.
- ^ Subramanian, S. (28 August 2019). "Making New Elements Doesn't Pay. Just Ask This Berkeley Scientist". Bloomberg Businessweek. Retrieved 2020-01-18.
- ^ a b c d e f Ivanov, D. (2019). "Сверхтяжелые шаги в неизвестное" [Superheavy steps into the unknown]. nplus1.ru (in Russian). Retrieved 2020-02-02.
- ^ Hinde, D. (2017). "Something new and superheavy at the periodic table". The Conversation. Retrieved 2020-01-30.
- .
- ISSN 2100-014X.
- ISBN 978-0-471-76862-3.
- ^ S2CID 28796927.
- S2CID 95737691.
- ^ S2CID 99193729.
- ^ a b c d Chemistry World (2016). "How to Make Superheavy Elements and Finish the Periodic Table [Video]". Scientific American. Retrieved 2020-01-27.
- ^ Hoffman, Ghiorso & Seaborg 2000, p. 334.
- ^ Hoffman, Ghiorso & Seaborg 2000, p. 335.
- ^ Zagrebaev, Karpov & Greiner 2013, p. 3.
- ^ Beiser 2003, p. 432.
- ^ a b Pauli, N. (2019). "Alpha decay" (PDF). Introductory Nuclear, Atomic and Molecular Physics (Nuclear Physics Part). Université libre de Bruxelles. Retrieved 2020-02-16.
- ^ a b c d e Pauli, N. (2019). "Nuclear fission" (PDF). Introductory Nuclear, Atomic and Molecular Physics (Nuclear Physics Part). Université libre de Bruxelles. Retrieved 2020-02-16.
- ISSN 0556-2813.
- ^ Audi et al. 2017, pp. 030001-129–030001-138.
- ^ Beiser 2003, p. 439.
- ^ a b Beiser 2003, p. 433.
- ^ Audi et al. 2017, p. 030001-125.
- S2CID 125849923.
- ^ Beiser 2003, p. 432–433.
- ^ ISSN 1742-6596.
- ^ Moller, P.; Nix, J. R. (1994). Fission properties of the heaviest elements (PDF). Dai 2 Kai Hadoron Tataikei no Simulation Symposium, Tokai-mura, Ibaraki, Japan. University of North Texas. Retrieved 2020-02-16.
- ^ . Retrieved 2020-02-16.
- PMID 25666065.
- Bibcode:1989nufi.rept...16H.
- S2CID 119531411.
- S2CID 239775403.
- ^ Howes, L. (2019). "Exploring the superheavy elements at the end of the periodic table". Chemical & Engineering News. Retrieved 2020-01-27.
- ^ Distillations. Retrieved 2020-02-22.
- ^ "Популярная библиотека химических элементов. Сиборгий (экавольфрам)" [Popular library of chemical elements. Seaborgium (eka-tungsten)]. n-t.ru (in Russian). Retrieved 2020-01-07. Reprinted from "Экавольфрам" [Eka-tungsten]. Популярная библиотека химических элементов. Серебро – Нильсборий и далее [Popular library of chemical elements. Silver through nielsbohrium and beyond] (in Russian). Nauka. 1977.
- ^ "Nobelium - Element information, properties and uses | Periodic Table". Royal Society of Chemistry. Retrieved 2020-03-01.
- ^ a b Kragh 2018, pp. 38–39.
- ^ Kragh 2018, p. 40.
- ^ (PDF) from the original on 25 November 2013. Retrieved 7 September 2016.
- .
- ^ ISBN 978-1-86094-087-3.
- ^ S2CID 195819585.
- .
- ^ a b c d e f Hoffman, D.C., Ghiorso, A., Seaborg, G. T. The Transuranium People: The Inside Story, (2000), 369–399
- ^ a b c d e "106 Seaborgium". Elements.vanderkrogt.net. Retrieved 12 September 2008.
- ^ a b Eric, Seaborg (2003). "Seaborgium". Chemical and Engineering News. 81 (36).
- ^ "The Nobel Prize in Chemistry 1951". Nobel Foundation. Retrieved August 26, 2012.
- S2CID 254117522. Retrieved 2 July 2023.
- ^ .
- ^ Armbruster, Peter & Munzenberg, Gottfried (1989). "Creating superheavy elements". Scientific American. 34: 36–42.
- .
- ^ a b c d Sonzogni, Alejandro. "Interactive Chart of Nuclides". National Nuclear Data Center: Brookhaven National Laboratory. Archived from the original on 2018-06-12. Retrieved 2008-06-06.
- S2CID 254658975.
- ^ Cite error: The named reference
Bloomberg
was invoked but never defined (see the help page). - ISBN 978-0-08-037941-8.
- S2CID 5172663.
- ^ S2CID 206558746. (subscription required)
- ISBN 9783642374661.
- S2CID 98583998. Archived from the original on 2014-10-25.)
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Bibliography
- Audi, G.; Kondev, F. G.; Wang, M.; et al. (2017). "The NUBASE2016 evaluation of nuclear properties". Chinese Physics C. 41 (3): 030001. .
- Beiser, A. (2003). Concepts of modern physics (6th ed.). McGraw-Hill. OCLC 48965418.
- ISBN 978-1-78-326244-1.
- ISBN 978-3-319-75813-8.
- Zagrebaev, V.; Karpov, A.; Greiner, W. (2013). "Future of superheavy element research: Which nuclei could be synthesized within the next few years?". S2CID 55434734.
External links
- Chemistry in its element podcast (MP3) from the Royal Society of Chemistry's Chemistry World: Seaborgium
- Seaborgium at The Periodic Table of Videos(University of Nottingham)
- WebElements.com – Seaborgium