Reactions of 8-quinolinol with covalent halides. Part IV. Pentachlorides and pentabromides of niobium and tantalum

Abstract

The reactions, in sealed tubes, of 8-quinolinol (oxH) with niobium or tantalum pentachlorides or pentabromides (MX₅) produce materials of composition MX₅,n(oxH)(n= 2, 4, 5, 6, 8, or 10). These materials are mixtures which on heating yield compounds of the type MX_m(ox)_5–m(m= 1–3). Compounds MX₄(ox) have also been prepared, affording all combinations of M, X, and m[except for NbBr₂(ox)₃]. NbBr(ox)₄ and TaBr(ox)₄ are 1:1 electrolytes, but conductance measurements and i.r. spectroscopy (4000–80 cm.^–1) indicate that the other compounds are nonelectrolytes with metal co-ordination numbers of 9, 8, 7, and 6 for m= 1–4.