Praseodymium compounds

Last updated

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.

Contents

Halides

Praseodymium(III) chloride in its heptahydrate form Praseodymium(III)-chloride-heptahydrate.jpg
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)

Praseodymium(III) fluoride is the most stable fluoride of praseodymium. It can be prepared the reaction between praseodymium(III) nitrate and sodium fluoride will produce praseodymium(III) fluoride as a green crystalline solid. [2] Praseodymium(III) chloride is a light green solid that can be prepared by treating praseodymium metal with hydrogen chloride. [3] [4] It is usually purified by vacuum sublimation. [5] It is Lewis acidic, classified as "hard" according to the 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 tetrafluoride, PrF4, is also known, and is produced by reacting a mixture of sodium fluoride and praseodymium(III) fluoride with fluorine gas, producing Na2PrF6, following which sodium fluoride is removed from the reaction mixture with liquid hydrogen fluoride. [8] Additionally, praseodymium forms a bronze 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. Praseodymium-oxygen system.png
Graph showing the praseodymium-oxygen system.

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

ValueFormulaPhasex in PrOxAverage oxidation state of Pr
4Pr2O3θ1.53
7Pr7O12ι1.7143.428
9Pr9O16ζ1.7783.556
10Pr5O9ε1.83.6
11Pr11O20δ1.8183.636
12Pr6O11β1.8333.667
∞PrO224

Organopraseodymium compounds

Organopraseodymium compounds are compounds with a praseodymium-to-carbon bond. These compounds are very similar to those of the other lanthanides, as they all share an inability to undergo π backbonding. They are thus mostly restricted to the mostly ionic cyclopentadienides (isostructural with those of lanthanum) and the σ-bonded simple alkyls and aryls, some of which may be polymeric. [22] The coordination chemistry of praseodymium is largely that of the large, electropositive Pr3+ ion, and is thus largely similar to those of the other early lanthanides La3+, Ce3+, and Nd3+. For instance, like lanthanum, cerium, and neodymium, praseodymium nitrate forms both the 4:3 and 1:1 complexes with 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]

Praseodymium(III,IV) oxide has a number of potential applications in chemical catalysis, and is often used in conjunction with a promoter such as sodium or gold to improve its catalytic performance. It has a high-K dielectric constant of around 30 and very low leakage currents [28] which have also made it a promising material for many potential applications in nanodevices and microelectronics. [20]

Pictures of praseodymium compounds

Related Research Articles

<span class="mw-page-title-main">Lanthanum</span> Chemical element, symbol La and atomic number 57

Lanthanum is a chemical element; it has symbol La and atomic number 57. It is a soft, ductile, silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table, of which lanthanum is the first and the prototype. Lanthanum is traditionally counted among the rare earth elements. Like most other rare earth elements, the usual oxidation state is +3, although some compounds are known with an oxidation state of +2. Lanthanum has no biological role in humans but is essential to some bacteria. It is not particularly toxic to humans but does show some antimicrobial activity.

The lanthanide or lanthanoid series of chemical elements comprises at least the 14 metallic chemical elements with atomic numbers 57–70, from lanthanum through ytterbium. In the periodic table, they fill the 4f orbitals. Lutetium is also sometimes considered a lanthanide, despite being a d-block element and a transition metal.

<span class="mw-page-title-main">Neodymium</span> Chemical element, symbol Nd and atomic number 60

Neodymium is a chemical element; it has symbol Nd and atomic number 60. It is the fourth member of the lanthanide series and is considered to be one of the rare-earth metals. It is a hard, slightly malleable, silvery metal that quickly tarnishes in air and moisture. When oxidized, neodymium reacts quickly producing pink, purple/blue and yellow compounds in the +2, +3 and +4 oxidation states. It is generally regarded as having one of the most complex spectra of the elements. Neodymium was discovered in 1885 by the Austrian chemist Carl Auer von Welsbach, who also discovered praseodymium. It is present in significant quantities in the minerals monazite and bastnäsite. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Neodymium is fairly common—about as common as cobalt, nickel, or copper—and is widely distributed in the Earth's crust. Most of the world's commercial neodymium is mined in China, as is the case with many other rare-earth metals.

<span class="mw-page-title-main">Praseodymium</span> Chemical element, symbol Pr and atomic number 59

Praseodymium is a chemical element; it has symbol Pr and the atomic number 59. It is the third member of the lanthanide series and is considered one of the rare-earth metals. It is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

<span class="mw-page-title-main">Cerium(III) chloride</span> Chemical compound

Cerium(III) chloride (CeCl3), also known as cerous chloride or cerium trichloride, is a compound of cerium and chlorine. It is a white hygroscopic salt; it rapidly absorbs water on exposure to moist air to form a hydrate, which appears to be of variable composition, though the heptahydrate CeCl3·7H2O is known. It is highly soluble in water, and (when anhydrous) it is soluble in ethanol and acetone.

<span class="mw-page-title-main">Praseodymium(III) chloride</span> Chemical compound

Praseodymium(III) chloride is the inorganic compound with the formula PrCl3. Like other lanthanide trichlorides, it exists both in the anhydrous and hydrated forms. It is a blue-green solid that rapidly absorbs water on exposure to moist air to form a light green heptahydrate.

Neodymium(III) chloride or neodymium trichloride is a chemical compound of neodymium and chlorine with the formula NdCl3. This anhydrous compound is a mauve-colored solid that rapidly absorbs water on exposure to air to form a purple-colored hexahydrate, NdCl3·6H2O. Neodymium(III) chloride is produced from minerals monazite and bastnäsite using a complex multistage extraction process. The chloride has several important applications as an intermediate chemical for production of neodymium metal and neodymium-based lasers and optical fibers. Other applications include a catalyst in organic synthesis and in decomposition of waste water contamination, corrosion protection of aluminium and its alloys, and fluorescent labeling of organic molecules (DNA).

<span class="mw-page-title-main">Samarium(III) chloride</span> Chemical compound

Samarium(III) chloride, also known as samarium trichloride, is an inorganic compound of samarium and chloride. It is a pale yellow salt that rapidly absorbs water to form a hexahydrate, SmCl3.6H2O. The compound has few practical applications but is used in laboratories for research on new compounds of samarium.

There are three sets of gallium halides, the trihalides where gallium has oxidation state +3, the intermediate halides containing gallium in oxidation states +1, +2 and +3 and some unstable monohalides, where gallium has oxidation state +1.

<span class="mw-page-title-main">Cerium(III) bromide</span> Chemical compound

Cerium(III) bromide is an inorganic compound with the formula CeBr3. This white hygroscopic solid is of interest as a component of scintillation counters.

<span class="mw-page-title-main">Cerium</span> Chemical element, symbol Ce and atomic number 58

Cerium is a chemical element; it has symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the oxidation state of +3 characteristic of the series, it also has a stable +4 state that does not oxidize water. It is also considered one of the rare-earth elements. Cerium has no known biological role in humans but is not particularly toxic, except with intense or continued exposure.

<span class="mw-page-title-main">Berkelium compounds</span> Chemical compounds

Berkelium forms a number of chemical compounds, where it normally exists in an oxidation state of +3 or +4, and behaves similarly to its lanthanide analogue, terbium. Like all actinides, berkelium easily dissolves in various aqueous inorganic acids, liberating gaseous hydrogen and converting into the trivalent oxidation state. This trivalent state is the most stable, especially in aqueous solutions, but tetravalent berkelium compounds are also known. The existence of divalent berkelium salts is uncertain and has only been reported in mixed lanthanum chloride-strontium chloride melts. Aqueous solutions of Bk3+ ions are green in most acids. The color of the Bk4+ ions is yellow in hydrochloric acid and orange-yellow in sulfuric acid. Berkelium does not react rapidly with oxygen at room temperature, possibly due to the formation of a protective oxide surface layer; however, it reacts with molten metals, hydrogen, halogens, chalcogens and pnictogens to form various binary compounds. Berkelium can also form several organometallic compounds.

Praseodymium(III) fluoride is an inorganic compound with the formula PrF3, being the most stable fluoride of praseodymium.

Lanthanide trichlorides are a family of inorganic compound with the formula LnCl3, where Ln stands for a lanthanide metal. The trichlorides are standard reagents in applied and academic chemistry of the lanthanides. They exist as anhydrous solids and as hydrates.

<span class="mw-page-title-main">Neodymium compounds</span> Chemical compounds with at least one neodymium atom

Neodymium compounds are compounds formed by the lanthanide metal neodymium (Nd). In these compounds, neodymium generally exhibits the +3 oxidation state, such as NdCl3, Nd2(SO4)3 and Nd(CH3COO)3. Compounds with neodymium in the +2 oxidation state are also known, such as NdCl2 and NdI2. Some neodymium compounds have colors that vary based upon the type of lighting.

Einsteinium compounds are compounds that contain the element einsteinium (Es). These compounds largely have einsteinium in the +3 oxidation state, or in some cases in the +2 and +4 oxidation states. Although einsteinium is relatively stable, with half-lives ranging from 20 days upwards, these compounds have not been studied in great detail.

<span class="mw-page-title-main">Terbium compounds</span> Chemical compounds with at least one terbium atom

Terbium compounds are compounds formed by the lanthanide metal terbium (Tb). Terbium generally exhibits the +3 oxidation state in these compounds, such as in TbCl3, Tb(NO3)3 and Tb(CH3COO)3. Compounds with terbium in the +4 oxidation state are also known, such as TbO2 and BaTbF6. Terbium can also form compounds in the 0, +1 and +2 oxidation states.

<span class="mw-page-title-main">Lanthanum(III) iodide</span> Chemical compound

Lanthanum(III) iodide is an inorganic compound containing lanthanum and iodine with the chemical formula LaI
3.

Lutetium compounds are compounds formed by the lanthanide metal lutetium (Lu). In these compounds, lutetium generally exhibits the +3 oxidation state, such as LuCl3, Lu2O3 and Lu2(SO4)3. Aqueous solutions of most lutetium salts are colorless and form white crystalline solids upon drying, with the common exception of the iodide. The soluble salts, such as nitrate, sulfate and acetate form hydrates upon crystallization. The oxide, hydroxide, fluoride, carbonate, phosphate and oxalate are insoluble in water.

References

  1. ↑ "Chemical reactions of Praseodymium". Webelements. Retrieved 9 July 2016.
  2. ↑ Lin Ma, Wei-Xiang Chen, Yi-Fan Zheng, Jie Zhao, Zhude Xu (May 2007). "Microwave-assisted hydrothermal synthesis and characterizations of PrF3 hollow nanoparticles". Materials Letters . 61 (13): 2765–2768. 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. Minerale10, 239 (1973),
  5. 1 2 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. ↑ Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford University Press. p. 421. ISBN   978-0-19-965763-6.
  8. 1 2 3 Greenwood and Earnshaw, p. 1240–2
  9. ↑ Schmid, B.; Hälg, B.; Furrer, A. (1987). "Structure and crystal fields of PrBr3 and PrCl3: A neutron study". J. Appl. Phys. 61 (8): 3426–3428. Bibcode:1987JAP....61.3426S. doi:10.1063/1.338741.
  10. 1 2 Haynes, William M. (2016-06-22). CRC Handbook of Chemistry and Physics. CRC Press. pp. 2016–2652. ISBN   978-1-4987-5429-3.
  11. 1 2 Asprey, L. B.; Keenan, T. K.; Kruse, F. H. (1964). "Preparation and Crystal Data for Lanthanide and Actinide Triiodides". Inorg. Chem. 3 (8): 1137–1141. doi:10.1021/ic50018a015.
  12. ↑ Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford University Press. p. 421. ISBN   978-0-19-965763-6.
  13. ↑ E. Warkentin, H. Bärnighausen (1979), "Die Kristallstruktur von Praseodymdiiodid (Modifikation V)", Zeitschrift für anorganische und allgemeine Chemie (in German), vol. 459, no. 1, pp. 187–200, doi:10.1002/zaac.19794590120
  14. ↑ Lide, David R. (1998), Handbook of Chemistry and Physics (87 ed.), Boca Raton, Florida: CRC Press, pp. 478, 523, ISBN   0-8493-0594-2
  15. ↑ Dabrowski, Jarek; Weber, Eicke R. (2004), Predictive Simulation of Semiconductor Processing, Springer, p. 264, 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. 1 2 Zinatloo-Ajabshir, Sahar; Salavati-Niasari, Masoud (2015). "Novel poly(ethyleneglycol)-assisted synthesis of praseodymium oxide nanostructures via a facile precipitation route". Ceramics International. 41 (1): 567–575. doi:10.1016/j.ceramint.2014.08.105.
  18. ↑ "Praseodymium Oxide (Pr6O11)". www.reade.com. Retrieved 2018-03-15.
  19. 1 2 Matović, Branko; Pantić, Jelena; Prekajski, Marija; Stanković, Nadežda; Bučevac, Dušan; Minović, Tamara; Čebela, Maria (2013). "Synthesis and characterization of Pr6O11 nanopowders". Ceramics International. 39 (3): 3151–3155. doi:10.1016/j.ceramint.2012.09.098.
  20. 1 2 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. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 643–4. ISBN   978-0-08-037941-8.
  22. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 1248–9. ISBN   978-0-08-037941-8.
  23. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 1244–8. ISBN   978-0-08-037941-8.
  24. ↑ Willauer, A.R.; Palumbo, C.T.; Fadaei-Tirani, F.; Zivkovic, I.; Douair, I.; Maron, L.; Mazzanti, M. (2020). "Accessing the +IV Oxidation State in Molecular Complexes of Praseodymium". Journal of the American Chemical Society. 142 (12): 489–493. doi:10.1021/jacs.0c01204. PMID   32134644. S2CID   212564931.
  25. ↑ J. J. Zuckerman (17 September 2009). Inorganic Reactions and Methods, The Formation of Bonds to Elements of Group IVB (C, Si, Ge, Sn, Pb). John Wiley & Sons. 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

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.