Praseodymium diiodide

Crystal structure
	__ Pr 3+ __ I -
General
Surname	Praseodymium diiodide
Ratio formula	PrI 2
Brief description	bronze colored solid
External identifiers / databases
Wikidata	Q16855776
properties
Molar mass	394.72 g mol −1
Physical state	firmly
Melting point	758 ° C
safety instructions
GHS hazard labeling ; no classification available
GHS hazard labeling ; no classification available
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Praseodymium diiodide is an inorganic chemical compound of praseodymium from the group of iodides .

Extraction and presentation

Praseodymium diiodide can be obtained by reducing praseodymium (III) iodide with praseodymium in a vacuum at 800 ° C to 900 ° C.

{\ displaystyle \ mathrm {Pr + 2 \ PrI_ {3} \ longrightarrow 3 \ PrI_ {2}}}

It can also be represented by reacting praseodymium with mercury (II) iodide .

{\ displaystyle \ mathrm {Pr + HgI_ {2} \ longrightarrow PrI_ {2} + Hg}}

The compound was first synthesized in 1961 by John D. Corbett.

properties

Praseodymium diiodide is an opaque, dark, compact solid with a strong gloss and a metal-like appearance and character. Therein Praseodymium is trivalent corresponding to Pr ³⁺ (I ^- ) ₂ e ^- . The connection is extremely hygroscopic and can only be stored and handled under carefully dried protective gas or in a high vacuum. In air, it changes into hydrates with moisture absorption , but these are unstable and more or less quickly transform into oxide iodides with the evolution of hydrogen. These processes take place much faster with water. Five different crystal structures are known of the compound . Under normal conditions, like lanthanum diiodide and cerium diiodide, it crystallizes in the MoSi ₂ structure type. The other modifications correspond to those of (II) 2H- MoS ₂ , (III) 3R-MoS ₂ , (IV) cadmium chloride and (V) a spinel -like type with Pr ₄ I ₈ units. The modification corresponding to cadmium chloride has a trigonal crystal structure with the space group R 3 m (space group no. 166) and the lattice parameters a = 426.5 pm, c = 2247.1 pm. The structure of modification V is cubic with the space group F 4 3 m (no. 216) and the lattice parameter a = 1239.9 pm. Template: room group / 166Template: room group / 216

Individual evidence

^ ^A ^b William M. Haynes: CRC Handbook of Chemistry and Physics, 93rd Edition . CRC Press, 2012, ISBN 1-4398-8049-2 , pp. 84 ( limited preview in Google Book search).
↑ ^a ^b ^c ^d Georg Brauer , with the assistance of Marianne Baudler a . a. (Ed.): Handbook of Preparative Inorganic Chemistry . 3rd, revised edition. tape I . Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , pp. 1081 .
↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
^ Gerd Meyer, Dieter Naumann, Lars Wesemann: Inorganic Chemistry in Focus III . John Wiley & Sons, 2006, ISBN 978-3-527-60909-3 , pp. 45 ( limited preview in Google Book search).
↑ Ralf Alsfasser, Erwin Riedel: Modern Inorganic Chemistry . Walter de Gruyter, 2007, ISBN 3-11-019060-5 , p. 366 ( limited preview in Google Book search).
↑ Niels Gerlitzki, Gerd Meyer, Anja-Verena Mudring, John D. Corbett: Praseodymium diiodide, PrI2, revisited by synthesis, structure determination and theory. In: Journal of Alloys and Compounds. 380, 2004, pp. 211-218, doi : 10.1016 / j.jallcom.2004.03.046 .

[William_M._Haynes-1] A ^b William M. Haynes: CRC Handbook of Chemistry and Physics, 93rd Edition . CRC Press, 2012, ISBN 1-4398-8049-2 , pp. 84 ( limited preview in Google Book search).

[brauer-2] Georg Brauer , with the assistance of Marianne Baudler a . a. (Ed.): Handbook of Preparative Inorganic Chemistry . 3rd, revised edition. tape I . Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , pp. 1081 .

[NV-3] This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.

[Gerd_Meyer,_Dieter_Naumann,_Lars_Wesemann-4] Gerd Meyer, Dieter Naumann, Lars Wesemann: Inorganic Chemistry in Focus III . John Wiley & Sons, 2006, ISBN 978-3-527-60909-3 , pp. 45 ( limited preview in Google Book search).

[Ralf_Alsfasser,_Erwin_Riedel-5] Ralf Alsfasser, Erwin Riedel: Modern Inorganic Chemistry . Walter de Gruyter, 2007, ISBN 3-11-019060-5 , p. 366 ( limited preview in Google Book search).

[DOI10.1016/j.jallcom.2004.03.046-6] Niels Gerlitzki, Gerd Meyer, Anja-Verena Mudring, John D. Corbett: Praseodymium diiodide, PrI2, revisited by synthesis, structure determination and theory. In: Journal of Alloys and Compounds. 380, 2004, pp. 211-218, doi : 10.1016 / j.jallcom.2004.03.046 .