Praseodymium compounds

Edit links
Source: Wikipedia, the free encyclopedia.
See also: Category:Praseodymium compounds

Praseodymium compounds are compounds formed by the lanthanide metal praseodymium (Pr). In these compounds, praseodymium generally exhibits the +3 oxidation state, such as PrCl3, Pr(NO3)3 and Pr(CH3COO)3. However, compounds with praseodymium in the +2 and +4 oxidation states, and unlike other lanthanides, the +5 oxidation state, are also known.

Halides

Praseodymium(III) chloride in its heptahydrate form

Praseodymium metal reacts with all the stable halogens to form green trihalides:[1]

2 Pr (s) + 3 F2 (g) → 2 PrF3 (s)
2 Pr (s) + 3 Cl2 (g) → 2 PrCl3 (s)
2 Pr (s) + 3 Br2 (g) → 2 PrBr3 (s)
2 Pr (s) + 3 I2 (g) → 2 PrI3 (s)

HSAB concept. Rapid heating of the hydrate may cause small amounts of hydrolysis.[5] PrCl3 forms a stable Lewis acid-base complex K2PrCl5 by reaction with potassium chloride; this compound shows interesting optical and magnetic properties.[6]

Praseodymium(III) bromide is the only stable bromide of praseodymium. It adopts the UCl3 crystal structure.[7] The praseodymium ions are 9-coordinate and adopt a tricapped trigonal prismatic geometry.[8] The praseodymium–bromine bond lengths are 3.05 Å and 3.13 Å.[9] Praseodymium(III) iodide can be prepared by heating praseodymium and iodine in an inert atmosphere produces praseodymium(III) iodide,[10] or by heating praseodymium with mercury(II) iodide.[11] It forms orthorhombic crystals which are hygroscopic.[10] It crystallizes in the PuBr3 type[11][12] with space group Cmcm (No. 63) with a = 4.3281(6) Å, b = 14.003(6) Å and c = 9.988(3) Å.[13]

The

diiodide; like the diiodides of lanthanum, cerium, and gadolinium, it is a praseodymium(III) electride compound.[8]

Oxides

Praseodymium can form many different oxides, although the only oxides that are stable at room temperature are Pr2O3, Pr6O11 and PrO2. Praseodymium(III) oxide is a green powder that forms hexagonal crystals,[14] and crystallizes in the manganese(III) oxide or bixbyite structure.[15] Praseodymium(IV) oxide can be produced by boiling Pr6O11 in water or acetic acid:[16]

Pr6O11 + 3 H2O → 4 PrO2 + 2 Pr(OH)3

Praseodymium(III,IV) oxide is the most stable form of the praseodymium oxides at ambient temperature and pressure.[17] It is soluble in water[18] and has a cubic fluorite structure.[19] It can be prepared via solid-state methods such as thermolysis, molten salt method, calcination or precipitation.[19][17][20]

Graph showing the praseodymium-oxygen system.

In addition to Pr6O11, praseodymium also forms a system of oxides at different phases:[21]

Value Formula Phase x in PrOx Average oxidation state of Pr
4 Pr2O3 θ 1.5 3
7 Pr7O12 ι 1.714 3.428
9 Pr9O16 ζ 1.778 3.556
10 Pr5O9 ε 1.8 3.6
11 Pr11O20 δ 1.818 3.636
12 Pr6O11 β 1.833 3.667
∞ PrO2 2 4

Organopraseodymium compounds

See also: Organolanthanide chemistry

Organopraseodymium compounds are compounds with a

18-crown-6, whereas the middle lanthanides from promethium to gadolinium can only form the 4:3 complex and the later lanthanides from terbium to lutetium cannot successfully coordinate to all the ligands. Such praseodymium complexes have high but uncertain coordination numbers and poorly defined stereochemistry, with exceptions resulting from exceptionally bulky ligands such as the tricoordinate [Pr{N(SiMe3)2}3]. There are also a few mixed oxides and fluorides involving praseodymium(IV), but it does not have an appreciable coordination chemistry in this oxidation state like its neighbour cerium.[23] However, the first example of a molecular complex of praseodymium(IV) has recently been reported.[24]
Like the other organolanthanide compounds, properties of organopraseodymium compounds include:

σ-Bonded complexes

Metal-carbon σ bonds are found in alkyls of praeodymium such as [PrMe6]3− and Pr[CH(SiMe3)2]3.

π-Bonded complexes

Cyclopentadienyl complexes, are known for praseodymium. It can be produced by the following reaction scheme:

3 Na[Cp] + PrCl3 → Pr[Cp]3 + 3 NaCl

These compounds are of limited use and academic interest.[25]

Applications

Praseodymium(III) nitride is used in high-end electric and semiconductor products, and as a raw material to produce phosphor. Also it is used as a magnetic material and sputtering target material.[26] Many praseodymium compounds, such as praseodymium(III) oxalate, are used to colour some glasses and enamels. If mixed with certain other materials, praseodymium(III) oxalate paints glass intense yellow.[27]

microelectronics.[20]

Pictures of praseodymium compounds

Praseodymium compounds

References

  1. ^ "Chemical reactions of Praseodymium". Webelements. Retrieved 9 July 2016.
  2. doi:10.1016/j.matlet.2006.04.124. Retrieved 2019-03-26.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  3. ^ J. Cybinska, J. Sokolnicki, J. Legendziewicz, G. Meyer, Journal of Alloys and Compounds, 341, 115–123 (2002).
  4. ^ L. F. Druding, J. D. Corbett, "Lower Oxidation States of the Lanthanides. Neodymium(II) Chloride and Iodide", J. Am. Chem. Soc. 83, 2462 (1961); J. D. Corbett, Rev. Chim. Minerale 10, 239 (1973),
  5. ^ a b F. T. Edelmann, P. Poremba, in: Synthetic Methods of Organometallic and Inorganic Chemistry, (W. A. Herrmann, ed.), Vol. 6, Georg Thieme Verlag, Stuttgart, 1997.
  6. ^ J. Cybinska, J. Sokolnicki, J. Legendziewicz, G. Meyer, Journal of Alloys and Compounds, 341, 115–123 (2002).
  7. ISBN 978-0-19-965763-6
    .
  8. ^ a b c Greenwood and Earnshaw, p. 1240–2
  9. doi:10.1063/1.338741
    .
  10. ^
    ISBN 978-1-4987-5429-3
    .
  11. ^
    doi:10.1021/ic50018a015
    .
  12. ISBN 978-0-19-965763-6
    .
  13. doi:10.1002/zaac.19794590120
  14. ISBN 0-8493-0594-2
  15. ISBN 978-3-540-20481-7
    , retrieved 2009-03-18
  16. ^ Chinese: 《无机化学丛书》.第七卷 钪 稀土元素. 科学出版社. 1.3.4 氧化态+4的化合物. P193~195
  17. ^
    doi:10.1016/j.ceramint.2014.08.105
    .
  18. ^ "Praseodymium Oxide (Pr6O11)". www.reade.com. Retrieved 2018-03-15.
  19. ^
    doi:10.1016/j.ceramint.2012.09.098
    .
  20. ^ a b Shamshi Hassan, M., Shaheer Akhtar, M., Shim, KB. et al. Morphological and Electrochemical Properties of Crystalline Praseodymium Oxide Nanorods. Nanoscale Res Lett 5, 735 (2010). https://doi.org/10.1007/s11671-010-9547-8
  21. ISBN 978-0-08-037941-8
    .
  22. ISBN 978-0-08-037941-8
    .
  23. ISBN 978-0-08-037941-8
    .
  24. S2CID 212564931
    .
  25. ISBN 978-0-470-14547-0
    . Retrieved 28 July 2013.
  26. ^ "Praseodymium Nitride (PrN) Powder". Stanford Advanced Materials. Retrieved 18 June 2021.
  27. ^ "Praseodymium Oxalate 99%-99.999% from Metall Rare Earth Limited". metall.com.cn. Retrieved 17 June 2021.
  28. ^ Osten HJ, Liu JP, P Gaworzewski, E Bugiel, Zaumseil P: IEDM Technical Digest 653. 2000.

See also

Retrieved from "https://en.wikipedia.org/w/index.php?title=Praseodymium_compounds&oldid=1219403247"