Tungsten(II) iodide
{{Chembox
| ImageFile=Mo6Cl12-xtal-1993-CM-3D-balls.png
|Section1={{Chembox Identifiers
| CASNo=13470-17-2
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 533504
| ChemSpiderID = 464830
| StdInChI=1S/2HI.W/h2*1H;/q;;+2/p-2
| StdInChIKey = BMKSRUJKNOBSHP-UHFFFAOYSA-L
| SMILES=[I-].[I-].[W+2]
}}
|Section2={{Chembox Properties
| Appearance= dark brown solid
| I=2|W=1
| MeltingPt= 800 °C (decomposes)
}}
|Section8={{Chembox Related
| OtherCompounds=tungsten(III) iodide
| OtherAnions=tungsten(II) chloride
tungsten(II) bromide
| OtherCations=chromium(II) iodide
molybdenum(II) iodide
}}
}}
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:{{Cite book |title=Handbuch der präparativen anorganischen Chemie. 3 |date=1981 |publisher=Enke |isbn=978-3-432-87823-2 |edition=3., umgearb. Aufl |location=Stuttgart}}
:{{chem2|6 WI3 -> [W6I8]I4 + 3 I2}}
It can also be formed by the displacement reaction of tungsten(II) chloride and iodine:
:{{chem2|[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.{{Cite book |last=Latscha |first=Hans Peter |title=Chemie der Elemente |last2=Mutz |first2=Martin |date=2011 |publisher=Springer |isbn=978-3-642-16915-1 |series=Chemie-Basiswissen |location=Berlin Heidelberg}}
:{{chem2|W + I2 <-> WI2}}
Tungsten(II) iodide can also be obtained by reacting tungsten hexacarbonyl with iodine.{{Cite book |last=Johnson |first=Brian Frederick Gilbert |title=Inorganic chemistry of the transition elements |date=1972 |publisher=Chemical society |isbn=978-0-85186-500-3 |series=A specialist periodical report |location=London}}
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.