Crystal and electronic structure of Ni3Bi2S2 (parkerite)

The crystal structure of parkerite, Ni3Bi2S2, was studied by single-crystal X-ray diffraction analysis and refined. The single crystal was prepared by the method of chemical transport reactions. The electronic structure of Ni3Bi2S2 was calculated by the extended Huckel and DFT-LMTO-ASA methods. Substantial delocalization of electrons in the vicinity of the Fermi level and the presence of the strong Ni-S and Ni-Bi bonds were revealed. The Ni-Ni bonds are weak, which is in agreement with the X-ray diffraction data.