Europium (II) iodide

Crystal structure
__ Eu 2+      __ I -
General
Surname	Europium (II) iodide
other names	Europium diiodide Europium iodide (ambiguous)
Ratio formula	EuI 2
Brief description	almost white solid
External identifiers / databases
CAS number 22015-35-6 EC number 244-721-0 ECHA InfoCard 100.040.641 PubChem 519914 Wikidata Q15628199
properties
Molar mass	405.77 g mol −1
Physical state	firmly
density	5.50 g cm −3
Melting point	510 ° C
boiling point	1120 ° C
solubility	soluble in tetrahydrofuran
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 315-317-319-334-360 P: 201-261-280-305 + 351 + 338-308 + 313
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Europium (II) iodide is an inorganic chemical compound of europium from the group of iodides .

Extraction and presentation

Europium (II) iodide can be obtained by reducing europium (III) iodide with hydrogen at 350 ° C.

${\displaystyle \mathrm {2\ EuI_{3}+H_{2}\longrightarrow 2\ EuI_{2}+2\ HI} }$

Also the representation through thermal decomposition of europium (III) iodide at 200 ° C

${\displaystyle \mathrm {2\ EuI_{3}\longrightarrow 2\ EuI_{2}+I_{2}} }$

or by reaction of europium with mercury (II) iodide is possible.

${\displaystyle \mathrm {Eu+HgI_{2}\longrightarrow EuI_{2}+Hg} }$

The reaction of europium with ammonium iodide in liquid ammonia at −78 ° C is also possible. First of all, the ammonia of europium (II) iodide is obtained, which can then be broken down at around 200 ° C in a high vacuum.

${\displaystyle \mathrm {Eu+2\ NH_{4}I\longrightarrow EuI_{2}+2\ NH_{3}+H_{2}} }$

Europium (II) iodide can also be obtained by direct reaction of europium with iodine.

${\displaystyle \mathrm {Eu+I_{2}\longrightarrow EuI_{2}} }$

properties

Europium (II) iodide is an almost white solid that 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. If they are heated in air, europium (III) oxide iodide is formed via an intermediate stage . The compound has a monoclinic crystal structure . At low temperatures, a modification is also known which has an orthorhombic crystal structure with the space group Pnma (space group no. 62) and is isotypic to that of strontium iodide .

Individual evidence

1. ↑ ^{a b c d e f g h} Georg Brauer , with the assistance of Marianne Baudler u. a. (Ed.): Handbook of Preparative Inorganic Chemistry . 3rd, revised edition. tape I . Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , pp. 1081 .
2. ↑ ^{a b c} Data sheet Europium (II) iodide, beads, −10 mesh, 99.999% trace metals basis from Sigma-Aldrich , accessed on April 26, 2014 ( PDF ).
3. ↑ ^{a b} Hartmut Börnighausen: Representation and crystal data of europium (II) -iodide EuJ2 and europium (III) -oxide iodide EuOJ. With 2 illustrations. In: Journal for Practical Chemistry. 14, 1961, pp. 313-322, doi : 10.1002 / prac.19610140417 .
4. ↑ Michal Wiecko: Complex divalent lanthanoids and alkaline earth metals and new bonds with metals of group 13 . Cuvillier Verlag, 2008, ISBN 3-86727-689-7 , p. 7 ( limited preview in Google Book search).
5. ^ Gschneidner: Handbook on the Physics and Chemistry of Rare Earths . Elsevier, 2009, ISBN 0-08-093257-6 , pp. 244 ( limited preview in Google Book search).
6. ↑ Michael Krings, Michael Wessel, Richard Dronskowski: EuI2, a low-temperature europium (II) iodide phase. In: Acta Crystallographica Section C Crystal Structure Communications. 65, 2009, pp. I66-i68, doi : 10.1107 / S0108270109038542 .