Niobium Sulphides

Definite sulphides of niobium have not been prepared. Solutions of alkali niobates do not yield precipitates with hydrogen sulphide or alkali sulphides, but some evidence of the formation of sulphides in the dry way has been obtained. When metallic niobium is heated with sulphur, direct combination takes place with the formation of a black powder, which is probably the disulphide, NbS₂. This compound is perhaps also formed by burning the hydride in sulphur vapour, or by the action at high temperatures of the mixed vapours of carbon bisulphide and hydrogen sulphide on niobium pentoxide. The analytical data for these preparations are not, however, conclusive.