NiGe2: a new intermetallic compound synthesized under high-pressure

A new nickel germanide, NiGe2, was synthesized under high pressure and temp erature condition and the crystal structure was solved by the Rietveld anal ysis of the powder X-ray diffraction data. Single phase NiGe2 was obtained from the stoichiometric mixture of elemental components by the reaction at 5.5 GPa and 700 degrees C. The compound crystallizes into orthorhombic stru cture with the space group Cmca, isostructural with CoGe2. Lattice paramete rs were determined to be a=10.830(5) Angstrom, b=5.763(3) Angstrom, c=5.762 (3) Angstrom. The structure contains isolated Ni-Ni bonds dong the a-axis. The compound is a metallic conductor with a temperature independent suscept ibility. (C) 2000 Elsevier Science S.A. All rights reserved.