Tungsten hexacarbonyl

Tungsten carbonyl

Colorless solid

Fixed

2.65 g · cm -3

150 ° C.

Insoluble in water

Risk

Template: Infobox chemical / molecular formula search is not possible

Tungsten hexacarbonyl is a chemical compound having the formula W (CO ) 6 This colorless compound is chromium and molybdenum as its analogs, a volatile, air-stable complex of tungsten present in the oxidation state zero. Tungsten hexacarbonyl was detected in trace concentrations in the gaseous exhalations of sewage sludge.

Representation

Tungsten hexacarbonyl is represented by the reduction of tungsten hexachloride ( WCl6 ) under Kohlenstoffmonoxiddruck. However, it is often made ​​in this manner in the laboratory, because the required equipment is expensive, and the compound can be acquired inexpensively.

It can be used as a halide acceptor instead of triethylaluminum in the reductive carbonylation and copper powder or Devarda alloy.

Properties and Structure

Tungsten hexacarbonyl has an octahedral ( Oh). The six Kohlenstoffmonoxidliganden are positioned radially around the central tungsten atom. The dipole moment of the complex is 0 Debye. The W- C distance is 207 pm. The wavenumber of the CO stretching vibration of the free νCO carbon monoxide is at 1998 cm -1. It is a stable 18- Valenzelektronenkomplex.

The compound is relatively stable in air. It is sparingly soluble in nonpolar organic solvents. Like all metal carbonyls is tungsten hexacarbonyl from improper handling of a potentially hazardous source of volatile metal and carbon monoxide.

Reactions

The Kohlenstoffmonoxidliganden in tungsten hexacarbonyl can be substituted by other ligands. It behaves similarly to the analogous molybdenum complex, but generally forms kinetically stable compounds.

A derivative is the dihydrogen complex W ( CO) 3 [P ( C6H11 ) 3] 2 (H2 ), which was shown in 1982 by Cuba. It is around the first known dihydrogen complex represented by the Hiebersche base reaction.

Up to three Kohlenstoffmonoxdliganden can be replaced by acetonitrile.

Use

Tungsten hexacarbonyl was used for the desulfurization of organosulfur compounds and as precursors of catalysts for alkene metathesis.

Tungsten hexacarbonyl is used in the technique of electron beam -induced deposition of a precursor. As it evaporates easily and decays by the electron beam, it provides an easily accessible source of tungsten atoms.