Tungsten dichloride dioxide

Tungsten dichloride dioxide, or Tungstyl chloride 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.

Tungsten dichloride dioxide
Tungsten(VI) dioxydichloride
Names
IUPAC name
Tungsten(VI) dichloride dioxide
Other names
  • Tungsten(VI) dioxydichloride
  • Tungsten dichloride dioxide
  • Tungstyl chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.033.496
EC Number
  • 236-862-1
  • 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
  • [O-2].[O-2].[Cl-].[Cl-].[W]
Properties
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
decomposes
Solubility slightly soluble in ethanol
Structure
orthorhombic
Hazards
GHS labelling:[1]
GHS07: Exclamation mark
Warning
H315, H319, H335
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

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]

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]

References
  1. "C&L Inventory". echa.europa.eu. Retrieved 12 December 2021.
  2. Tillack, J. (1973). "Tungsten Oxyhalides". Inorganic Syntheses. pp. 109–122. doi:10.1002/9780470132456.ch22. ISBN 9780470132456. {{cite book}}: |journal= ignored (help)
  3. Gibson, V. C.; Kee, T. P.; Shaw, A. (1988). "New, improved synthesis of the group 6 oxyhalides, W(O)Cl4, W(O)2Cl2 and Mo(O)2Cl2". Polyhedron. 7 (7): 579–80. doi:10.1016/S0277-5387(00)86336-6.
  4. Ward, Brian G.; Stafford, Fred E. (1968). "Synthesis and Structure of Four- and Five-Coordinated Gaseous Oxohalides of Molybdenum(VI) and Tungsten(VI)". Inorganic Chemistry. 7 (12): 2569–2573. doi:10.1021/ic50070a020.
  5. Jarchow, O.; Schröder, F.; Schulz, H. "Kristallstruktur und Polytypie von WO2Cl2" Zeitschrift für anorganische und allgemeine Chemie 1968, vol. 363, p. 345ff. doi:10.1002/zaac.19683630108
  6. Holleman, A. F.; Wiberg, E. Inorganic Chemistry Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
  7. K. Dreisch, C. Andersson, C. Stalhandske "Synthesis and structure of dimethoxyethane-dichlorodioxo-tungsten(VI)—a highly soluble derivative of tungsten dioxodichloride" Polyhedron 1991, volume 10, p. 2417. doi:10.1016/S0277-5387(00)86203-8
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