Tungsten dichloride dioxide

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

Tungsten dichloride dioxide

Tungsten(VI) dioxydichloride
Names
IUPAC name Tungsten(VI) dichloride dioxide
Other names Tungsten(VI) dioxydichloride Tungsten dichloride dioxide Tungstyl chloride
Identifiers
CAS Number	13520-76-8 Y
3D model (JSmol)	Interactive image
ChemSpider	10652408
ECHA InfoCard	100.033.496
EC Number	236-862-1
PubChem CID	19092009
CompTox Dashboard (EPA)	DTXSID90894995
InChI InChI=1S/2ClH.2O.W/h2*1H;;;/q;;2*-2;/p-2 Key: DVBXMVWZPVBSJY-UHFFFAOYSA-L 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	286.74 g·mol−1
Appearance	Yellow-red crystals
Density	4.67 g/cm3
Melting point	265 °C (509 °F; 538 K)
Boiling point	Sublimes at > 350 °C in vacuum
Solubility in water	decomposes
Solubility	slightly soluble in ethanol
Structure
Crystal structure	orthorhombic
Hazards
GHS labelling:[1]
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Related compounds
Other anions	Tungsten dibromide dioxide Tungsten difluoride dioxide Tungsten diiodide dioxide
Other cations	Molybdenum dichloride dioxide
Related compounds	Chromyl chloride Tungsten hexachloride Tungsten(VI) oxytetrachloride Uranyl chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

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.^[2] An alternative route highlights the oxophilicity of tungsten:^[3]

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

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

Structure

Gaseous tungsten dichloride dioxide is a monomer.^[4] Solid tungsten dichloride dioxide is a polymer consisting of distorted octahedral W centres. The polymer 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 dative W-O bond.^[5]

Related oxyhalides

Tungsten forms a number of oxyhalides including WOCl₄, WOCl₃, WOCl₂. The corresponding bromides (WOBr₄, WOBr₃, WOBr₂) are also known as is WO₂I₂.^[6]

Reactions

Structure of the complex WO₂Cl₂(dimethoxyethane).

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.^[7]