Tungsten(II) iodide

(Redirected from Tungsten diiodide)

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

Tungsten(II) iodide
Identifiers
3D model (JSmol)
ChemSpider
  • InChI=1S/2HI.W/h2*1H;/q;;+2/p-2
    Key: BMKSRUJKNOBSHP-UHFFFAOYSA-L
  • [I-].[I-].[W+2]
Properties
I2W
Molar mass 437.65 g·mol−1
Appearance dark brown solid[1]
Density 6.79 g·cm−3[2]
Melting point 800 °C (decomposes)[2]
insoluble[2]
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).

Preparation

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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

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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

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  1. ^ a b c d Handbuch der präparativen anorganischen Chemie. 3 (3., umgearb. Aufl ed.). Stuttgart: Enke. 1981. ISBN 978-3-432-87823-2.
  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.
  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.