Strukturchemische Untersuchungen an Scandium-Cobalt-Phosphiden mit einem Metall:Phosphor-Verhältnis von 2:1

Abstract

Abstract Several new scandium cobalt phosphides were prepared by reaction of the elemental components in a tin flux. ScCoP has a TiNiSi-type structure with the orthorhombic lattice constants a = 6.268(2) Å , b = 3.750(1) Å , c = 7.050(3) Å. ScCo5P3 is isotypic with YCo5P3. Its orthorhombic lattice constants are: a = 11.691(5) Å , b = 3.583(1) Å , c = 10.206(3) Å. Sc2Co12P7crystallizes with the hexagonal Zr2Fe12P7 structure with a = 8.973(3) Å, c = 3.531(1) Å. Sc5Co19P12 is of a new type which is closely related to the structure of Hf2Co4P3. It has hexagonal symmetry, space group P6̄2m -D3h 3 and the lattice constants a - 12.124(7) Å , c = 3.633(2) Å , with Z = 1 formula unit per cell. The structure was determined and refined with isotropic thermal parameters from single-crystal counter data to a residual of R = 0.023 for 848 unique structure factors and 24 variable parameters. Considering the environments of the phosphorus atoms the structures are all closely related. There are, however, considerable differences in the coordination polyhedra of the metal atoms.