Tungsten(II) iodide

Tungsten(II) iodide
Identifiers
CAS Number	13470-17-2 ;
3D model (JSmol)	Interactive image;
ChemSpider	464830;
PubChem CID	533504;
	InChI InChI=1S/2HI.W/h2*1H;/q;;+2/p-2 Key: BMKSRUJKNOBSHP-UHFFFAOYSA-L;
	SMILES [I-].[I-].[W+2];
Properties
Chemical formula	I2W
Molar mass	437.65 g·mol−1
Appearance	dark brown solid
Density	6.79 g·cm−3
Melting point	800 °C (decomposes)
Solubility in water	insoluble
Related compounds
Other anions	tungsten(II) chloride; tungsten(II) bromide
Other cations	chromium(II) iodide; molybdenum(II) iodide
Related compounds	tungsten(III) iodide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Tungsten(II) iodide is an iodide of tungsten, with the chemical formula [W₆I₈]I₄, or abbreviated as WI₂.

Preparation

Tungsten diiodide can obtained from the decomposition from tungsten(III) iodide:^[1]

6 WI₃ → [W₆I₈]I₄ + 3 I₂

It can also be formed by the displacement reaction of tungsten(II) chloride and iodine:^[1]

[W₆Cl₈]Cl₄ + 12 I → [W₆I₈]I₄ + 12 Cl

It can also be formed by the direct reaction of tungsten and iodine, which is a reversible reaction. This reaction can be used in halogen lamps.^[3]

W + I₂ ⇌ WI₂

Tungsten(II) iodide can also be obtained by reacting tungsten hexacarbonyl with iodine.^[4]

Properties

Tungsten(II) iodide is a dark brown-colored solid that is stable in air and moisture. Its structure is the same as tungsten(II) chloride, crystallising orthorhombic crystal system, with space group Bbem (No. 64), and lattice parameters a = 1258 pm, b = 1259 pm, c = 1584 pm.^[1]

References

^ ^a ^b ^c ^d Handbuch der präparativen anorganischen Chemie. 3 (3., umgearb. Aufl ed.). Stuttgart: Enke. 1981. ISBN 978-3-432-87823-2.
^ ^a ^b ^c Haynes, William M.; Lide, David R.; Bruno, Thomas J. (2012). CRC handbook of chemistry and physics: a ready reference book of chemical and physical data (93rd ed.). Boca Raton: CRC. ISBN 978-1-4398-8049-4.
^ Latscha, Hans Peter; Mutz, Martin (2011). Chemie der Elemente. Chemie-Basiswissen. Berlin Heidelberg: Springer. ISBN 978-3-642-16915-1.
^ Johnson, Brian Frederick Gilbert (1972). Inorganic chemistry of the transition elements. A specialist periodical report. London: Chemical society. ISBN 978-0-85186-500-3.

[brauer-1] Handbuch der präparativen anorganischen Chemie. 3 (3., umgearb. Aufl ed.). Stuttgart: Enke. 1981. ISBN 978-3-432-87823-2.

[W._M._Haynes-2] Haynes, William M.; Lide, David R.; Bruno, Thomas J. (2012). CRC handbook of chemistry and physics: a ready reference book of chemical and physical data (93rd ed.). Boca Raton: CRC. ISBN 978-1-4398-8049-4.

[Hans_Peter_Latscha,_Martin_Mutz-3] Latscha, Hans Peter; Mutz, Martin (2011). Chemie der Elemente. Chemie-Basiswissen. Berlin Heidelberg: Springer. ISBN 978-3-642-16915-1.

[4] Johnson, Brian Frederick Gilbert (1972). Inorganic chemistry of the transition elements. A specialist periodical report. London: Chemical society. ISBN 978-0-85186-500-3.

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