Europium(II) iodide

(Redirected from Europium diiodide)

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

Europium(II) iodide
Names
IUPAC name
Europium(II) iodide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.040.641 Edit this at Wikidata
EC Number
  • 244-721-0
  • InChI=1S/Eu.2HI/h;2*1H/q+2;;/p-2
    Key: DPYXWFUVSMSNNV-UHFFFAOYSA-L
  • I[Eu]I
Properties
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)
Soluble in THF
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Preparation

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

Reduction of europium(III) iodide with hydrogen gas at 350 °C:[1]

2 EuI3 + H2 → 2 EuI2 + 2 HI

Thermal decomposition of europium(III) iodide at 200 °C:[1]

2 EuI3 → 2 EuI2 + 2 I2

Reaction of europium with mercury(II) iodide:[1]

Eu + HgI2 → Eu I2 + Hg

Reaction of europium with ammonium iodide:[1]

Eu + 2 NH4I → EuI2 + 2 NH3 + H2

Structure

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Europium(II) iodide has several polymorphs.[2] It adopts a monoclinic crystal structure in space group P 21/c (no. 14).[3][4]

It also adopts an orthorhombic polymorph in space group Pbca (no. 61). This form is isostructural with strontium iodide.[5]

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.[6]

References

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  1. ^ a b c d Brauer, Georg (1975). Handbook of Preparative Inorganic Chemistry. ISBN 3-432-02328-6.
  2. ^ Wells, A. F. (1984). Structural Inorganic Chemistry (5th ed.). Oxford University Press. pp. 415–416. ISBN 978-0-19-965763-6.
  3. ^ Bärnighausen, H.; Beck, H.; Grueninger, H. W.; Rietschel, E. T.; Schultz, N. (1969). "Neue AB2-strukturtypen mit siebenfach koordiniertem kation". Z. Kristallogr. 128: 430.
  4. ^ 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.
  5. ^ Bärnighausen, H.; Beck, H. P.; Grueninger, H. W. (1971). "Search Results - Access Structures". Rare Earths Mod. Sci. Technol. 9: 74–.
  6. ^ 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.