THE PRODUCTION AND THE PHYSICOCHEMICAL PROPERTIES OF NIOBIUM SULFIDE

Abstract : Synthesis of niobium sulfide (Nb2S3) from metallic niobium and niobium oxide and the physicochemical properties of the NbS(1.6) product were investigated. It was found that the optimum conditions for converting metallic niobium or niobium oxide into NbS(1.6) are identical and consist of passing a H2S stream over these materials at 1000-1300C for 2-4 hours. The content of the free sulfur in the niobium sulfide products varied within the 0.1-0.2% range. It was found that NbS(1.6) is stable toward boiling water and that it decomposes on treatment with concentrated sulfuric acid, concentrated or diluted nitric acid, and hydrogen peroxide. The NbS(1.6) was found to be stable toward oxygen up to 300C, to oxidize above 300C, and to oxidize to Nb2O3 within 10 minutes at 400C. X-ray examination indicated that in Nb2S(3.2)-Nb2S(3.59, the niobium sulfide has a rhombic lattice.