IR Study of the Transformation of WF6 on a W Substrate

Resumo

A new IR-spectroscopy (infrared) technique allowing investigation of the transformation of gaseous WF₆ on a W surface heated up to 860 K in a hydrogen and argon atmosphere is proposed. The weak chemical adsorption of WF₆ on W substrates is observed. The intermediate reaction products of WF₆ with solid W above 670 K are penta- and tetra-tungsten fluorides. The presence of other low-valent tungsten fluorides is possible in the form of adsorbed oligomeric molecules (dimers or trimers). It is shown that low-valent tungsten fluorides are strongly adsorbed on the surface of W. The adsorbed layers formed on the W substrate in the WF₆ + H₂ mixture and pure WF₆ str identical in composition.