Europium(II) iodide

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

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-2 Key: DPYXWFUVSMSNNV-UHFFFAOYSA-L
SMILES I[Eu]I
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 [77 °F], 100 kPa). Infobox references

Preparation

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

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]