Tungsten dichloride dioxide

Tungsten(VI) dioxydichloride
Other names

tungsten(VI) dioxydichloride
Identifiers
CAS number 13520-76-8 Y
Properties
Molecular formula WO2Cl2
Molar mass 286.75 g/mol
Appearance yellow crystals
Density 4.67 g/cm3, solid
Melting point

265 °C, 538 K, 509 °F
Boiling point

sublimes > 350 °C in vacuo
Solubility in water decomposes
Structure
Crystal structure orthorhombic
Hazards
EU classification not listed
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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

Contents

Preparation

WO2Cl2 is prepared by ligand redistribution reaction:

2 WO3 + WCl6 → 3 WO2Cl2

Using a two-zone 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.[1] An alternative route highlights the oxophilicity of tungsten:[2]

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

This reaction, like the preceding one, proceeds via the intermediacy of W(O)Cl4.

Other tungsten oxy chlorides

Tungsten forms a number of oxyhalides including WOCl4, WOCl3, WOCl2. The corresponding bromides are also known as is WO2I2.[3]

Reactions

WO2Cl2 is a Lewis acid, forming soluble adducts of the type WO2Cl2L2, where L is a donor ligand such as bipyridine.

References

  1. ^ Tillack, J.; Brown, T. M.; Schfer, H. (1973). "Tungsten Oxyhalides". Inorg. Synth. 14: 109–122. doi:10.1002/9780470132456.ch22. 
  2. ^ 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. 
  3. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.