Tungsten(V) oxytrichloride and oxytribromide. Part I. Preparation, structure, and a comparison with the analogous molybdenum(V) oxytrihalides

Abstract

The oxytrihalides WOCl₃ and WOBr₃ have been prepared by reduction of the corresponding tungsten(IV) oxytetrahalides with aluminium powder. A new preparative method for molybdenum(V) oxytribromide is also described. X-Ray powder photographs and temperature-range magnetic properties of these three halides and of MoOCl₃ indicate that, while the former have the NbOCl₃ structure with bridging M–O–M groups, the latter contains a terminal Mo–O bond with bridging solely through chlorine atoms.