Tungsten dichloride dioxide

Tungsten(VI) dioxydichloride

Tungsten(VI) dioxydichloride
Names
Other names tungsten(VI) dioxydichloride
Identifiers
CAS Number	13520-76-8 Y
EC Number	236-862-1
Jmol 3D model	Interactive image
PubChem	19092009
InChI InChI=1S/2ClH.2O.W/h2*1H;;;/q;;2*-2;/p-2
SMILES [O-2].[O-2].[Cl-].[Cl-].[W]
Properties
Chemical formula	WO2Cl2
Molar mass	286.749 g/mol
Appearance	yellow crystals
Density	4.67 g/cm3, solid
Melting point	265 °C (509 °F; 538 K)
Boiling point	sublimes > 350 °C in vacuo
Solubility in water	decomposes
Structure
Crystal structure	orthorhombic
Vapor pressure	{{{value}}}
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Tungsten dichloride dioxide is the chemical compound with the formula WO₂Cl₂. It is a yellow-colored solid. It is used as a precursor to other tungsten compounds. Like other tungsten halides, WO₂Cl₂ is sensitive to moisture, undergoing hydrolysis.

Preparation

WO₂Cl₂ is prepared by ligand redistribution reaction from tungsten trioxide and tungsten hexachloride:

2 WO₃ + WCl₆ → 3 WO₂Cl₂

Using a two-zone tube furnace, a vacuum-sealed tube containing these solids is heated to 350 °C. The yellow product sublimes to the cooler end of the reaction tube. No redox occurs in this process. An alternative route highlights the oxophilicity of tungsten:

WCl₆ + 2 O(Si(CH₃)₃)₂ → 3 WO₂Cl₂ + 4 ClSi(CH₃)₃

This reaction, like the preceding one, proceeds via the intermediacy of WOCl₄.

Structure

The compound is a polymer consisting of distorted octahedral W centres. The monomer is characterized by two short W-O distances, typical for a multiple W-O bond, and two long W-O distances more typical of a single or datice W-O bond.

Other tungsten oxy chlorides and related oxy halides

Tungsten forms a number of oxyhalides including WOCl₄, WOCl₃, WOCl₂. The corresponding bromides (WOBr₄, WOBr₃, WOBr₂) are also known as is WO₂I₂.

File:WO2Cl2(dme).png

Structure of the complex WO₂Cl₂(dimethoxyethane).

Reactions

WO₂Cl₂ is a Lewis acid, forming soluble adducts of the type WO₂Cl₂L₂, where L is a donor ligand such as bipyridine and dimethoxyethane. Such complexes often cannot be prepared by depolymerization of the inorganic solid, but are generated in situ from WOCl₄.