The Superconductivity of Some Transition Metal Compounds

About eighty transition metal compounds comprising borides, carbides, nitrides, oxides, silicides, and germanides of metals of Groups 4A, 5A, and 6A were tested for superconductivity down to 1.20°K, using a magnetic method. Among the specimens were most of the known compounds of the above type not examined magnetically for superconducting behavior by previous workers, and in all cases the structures were checked by x-ray diffraction analysis. The following eleven new superconductors were discovered, with the transition temperatures (°K) shown in parentheses: W₂B (3.10°), Nb₂C (9.18°), Ta₂C (3.26°), Nb₄N₃ (7.2°), V₃Si (17.1°), V₃Ge (6.01°), Mo₃Si (1.30°), Mo₃Ge (1.43°), α-ThSi₂ (3.16°), β-ThSi₂ (2.41°), and W₃Si₂ (2.84°). These compounds include the first superconducting germanides, V₃Ge and Mo₃Ge, which, together with V₃Si and Mo₃Si, crystallize in the cubic β-tungsten structure. The transition temperature of V₃Si is apparently the highest known for any binary superconducting compound.