Synthesis and crystal structure of Hf2Te

Article abstract of DOI:10.1016/S0925-8388(96)02880-0

Hf₂Te was prepared by arc-melting appropriate compressed mixtures of HfTe₂ and hafnium. The structure of the new hafnium-rich telluride was determined by means of powder diffractometry, R_B=0.0565. Hf₂Te adopts a Nb₂Se-type structure, monoclinic, space group C2/m, Z=8, Pearson symbol mS24, a= 1516.3(2) pm, b=370.26(4) pm, c= 1006.4(1) pm, β=90.50(1)°. The structure comprises pairwise interpenetrating columns of trans-face-shared centred Hf₉ cuboids. The columns form puckered slabs which are interconnected by homo- and heteronuclear bonds. Tellurium atoms are one-sidedly coordinated by six hafnium atoms. The coordination configurations about the two distinct tellurium atoms represent Hf₆Te hypho-fragments of a tri-capped trigonal prismatic Hf₉Te closo-cluster. Characteristic features of four other M₂Q structure types are elucidated. The valence electron concentration available for metal-metal bonding together with the cohesive energy of the respective metal are found to control the formation of the various M₂Q metal partial structures.