Europium(II) iodide - Misplaced Pages

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Europium(II) iodide
Names

IUPAC name Europium(II) iodide
Identifiers
CAS Number	22015-35-6
3D model (JSmol)	Interactive image
ChemSpider	80445
ECHA InfoCard	100.040.641
EC Number	244-721-0
PubChem CID	519914
CompTox Dashboard (EPA)	DTXSID90944621
InChI InChI=1S/Eu.2HI/h;2*1H/q+2;;/p-2Key: DPYXWFUVSMSNNV-UHFFFAOYSA-L
SMILES II
Properties
Chemical formula	EuI ₂
Molar mass	405.77 g/mol
Appearance	Tea yellow powder
Melting point	510 °C (950 °F; 783 K)
Boiling point	1,120 °C (2,050 °F; 1,390 K)
Solubility in water	Soluble in THF
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Infobox references

Chemical compound

Europium(II) iodide is the iodide salt of divalent europium cation.

Preparation

Europium(II) iodide can be prepared in a handful of ways, including:

Reduction of europium(III) iodide with hydrogen gas at 350 °C:

2 EuI₃ + H₂ → 2 EuI₂ + 2 HI

Thermal decomposition of europium(III) iodide at 200 °C:

2 EuI₃ → 2 EuI₂ + 2 I₂

Reaction of europium with mercury(II) iodide:

Eu + HgI₂ → Eu I₂ + Hg

Reaction of europium with ammonium iodide:

Eu + 2 NH₄I → EuI₂ + 2 NH₃ + H₂

Structure

Europium(II) iodide has several polymorphs. It adopts a monoclinic crystal structure in space group P 2₁/c (no. 14).

It also adopts an orthorhombic polymorph in space group Pbca (no. 61). This form is isostructural with strontium iodide.

A third polymorph of europium(II) iodide is formed if it is prepared from europium and ammonium iodide at low temperatures (200 K) in liquid ammonia. This low-temperature phase is orthorhombic and in space group Pnma (no. 62). This is the same structure as modification IV of strontium iodide.

References

^ Brauer, Georg (1975). Handbook of Preparative Inorganic Chemistry. ISBN 3-432-02328-6.
Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford University Press. pp. 415–416. ISBN 978-0-19-965763-6.
Bärnighausen, H.; Beck, H.; Grueninger, H. W.; Rietschel, E. T.; Schultz, N. (1969). "Neue AB₂-strukturtypen mit siebenfach koordiniertem kation". Z. Kristallogr. 128: 430.
Bärnighausen, H.; Schulz, N. (1969). "Die Kristallstruktur der monoklinen Form von Europium(II)-jodid EuJ₂". Acta Crystallogr. B. 25: 1104–1110. doi:10.1107/S0567740869003591.
Bärnighausen, H.; Beck, H. P.; Grueninger, H. W. (1971). "Search Results - Access Structures". Rare Earths Mod. Sci. Technol. 9: 74–.
Krings, M.; Wessel, M.; Dronskowski, R. (2009). "EuI₂, a low-temperature europium(II) iodide phase". Acta Crystallogr. C. 65: i66 – i68. doi:10.1107/S0108270109038542.