Tungsten (II) iodide

Crystal structure
__ W 2+      __ I -
General
Surname	Tungsten (II) iodide
other names	Tungsten diiodide
Ratio formula	WI 2
Brief description	ocher to black solid
External identifiers / databases
CAS number 13470-17-2 PubChem 533504 ChemSpider 464830 Wikidata Q4202645
properties
Molar mass	437.65 g mol −1
Physical state	firmly
density	6.79 g cm −3
Melting point	800 ° C (decomposition)
solubility	almost insoluble in water
safety instructions
GHS hazard labeling no classification available
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Tungsten (II) iodide is an inorganic chemical compound of tungsten from the group of iodides .

Extraction and presentation

Tungsten (II) iodide can be obtained by decomposing tungsten (III) iodide .

${\displaystyle \mathrm {6\ WI_{3}\longrightarrow [W_{6}I_{8}]I_{4}+3\ I_{2}} }$

It is also possible to obtain it from tungsten (II) chloride by halogen exchange reaction

${\displaystyle \mathrm {[W_{6}Cl_{8}]Cl_{4}+12\ I^{-}\longrightarrow [W_{6}I_{8}]I_{4}+12Cl^{-}} }$

or by reaction of tungsten (VI) chloride with hydrogen iodide at 110 ° C and subsequent degradation at 500 ° C in vacuo.

It is also formed reversibly when iodine reacts with tungsten, which is used to extend the service life of halogen lamps .

${\displaystyle \mathrm {W+2\ I\rightleftharpoons WI_{2}} }$

The reaction of tungsten hexacarbonyl with iodine also produces tungsten (II) iodide.

properties

Tungsten (II) iodide is an ocher-colored to black solid that is stable in air and to moisture at room temperature. It has a crystal structure isotypic to that of tungsten (II) chloride, it crystallizes orthorhombically in the space group Bbem (space group no.64 , position 5) with the lattice parameters a = 1258 pm, b = 1259 pm, c = 1584 pm.

Individual evidence

1. ↑ ^{a b c d e f} Georg Brauer: Handbook of preparative inorganic chemistry . 3., reworked. Edition. tape III . Enke, Stuttgart 1981, ISBN 3-432-87823-0 , pp. 1564 .
2. ↑ ^{a b c} W. M. Haynes (Ed.): CRC handbook of chemistry and physics. A ready-reference book of chemical and physical data . founded by David R. Lide. 93rd edition. CRC Press, Boca Raton 2012, ISBN 978-1-4398-8049-4 , pp. 4–96 (English, limited preview in Google Book Search).
3. ↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
4. ↑ Hans Peter Latscha, Martin Mutz: Chemistry of the elements . Springer, 2011, ISBN 3-642-16915-5 , pp. 231 ( limited preview in Google Book search).
5. ^ BFG Johnson: Inorganic Chemistry of the Transition Elements . Royal Society of Chemistry, 1972, ISBN 0-85186-500-3 , pp. 94 ( limited preview in Google Book search).
6. ↑ The former name of this group of rooms was Bbam .