Vanadium (II) iodide

Crystal structure
__ V 2+      __ I -
General
Surname	Vanadium (II) iodide
other names	Vanadium diiodide Vanadium (II) iodide Vanadium diiodide
Ratio formula	VI 2
Brief description	red-violet, crystalline solid
External identifiers / databases
CAS number 15513-84-5 EC number 239-545-6 ECHA InfoCard 100.035.935 PubChem 84959 Wikidata Q1541465
properties
Molar mass	304.75 g mol −1
Physical state	firmly
density	5.44 g cm −3
Melting point	≈ 800 ° C
boiling point	850 ° C
solubility	dissolves in water with formation of [V (H 2 O) 6 ] 2+ ions
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Vanadium (II) iodide is a chemical compound of the elements vanadium and iodine .

Extraction and presentation

Vanadium (II) iodide can be obtained by disproportionation of vanadium (III) iodide at 280 ° C:

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

The representation from the elements at around 500 ° C is also possible. If the reaction takes place with a slight excess of iodine, the black form of the compound is created.

${\displaystyle \mathrm {V+I_{2}\longrightarrow VI_{2}} }$

properties

Physical Properties

Vanadium (II) iodide comes in two forms. The red form only dissolves after several hours in moist air. In water it dissolves only slowly, but completely, even when heated. In contrast, the black form is as sensitive to moisture as vanadium (III) iodide . The red form has very thin leaflets, the black appears in hexagonal columns. The trigonal crystal structure of the red form corresponds to the trigonal form of cadmium (II) iodide with the space group P 3 m 1 (space group no.164 ) and the lattice parameters a = 4,000 Å , c = 6,670 Å.

Chemical properties

Vanadium (II) iodide is a powerful reducing agent that even reduces nitrogen to hydrazine in the presence of magnesium hydroxide .

It dissolves in water with the formation of [V (H ₂ O) ₆ ] ²⁺ ions:

${\displaystyle \mathrm {V^{2+}+6\ H_{2}O\longrightarrow [V(H_{2}O)_{6}]^{2+}} }$

Individual evidence

1. ^ ^{A b} A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1545.
2. ↑ ^{a b} Vanadium (II) iodide on webelements.com
3. ^ ^{A b c} A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 , p. 1550.
4. ↑ There is not yet a harmonized classification for this substance . A labeling of vanadium diiodide in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), retrieved on July 28, 2019, is reproduced from a self-classification by the distributor .
5. ↑ Lothar Kolditz: Inorganic Chemistry Part 2 . VEB Deutscher Verlag der Wissenschaften, Berlin, 1980, p. 641.
6. ↑ ^{a b} Georg Brauer (Ed.) U. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume III, Ferdinand Enke, Stuttgart 1981, ISBN 3-432-87823-0 , p. 1413.