SYNTHESIS, PROPERTIES AND CRYSTAL-STRUCTURE OF ZR6ZN23SI WITH FILLED TH6MN23 TYPE-STRUCTURE

The new compound Zr6Zn23Si has been prepared by a solid state reaction of a zirconium-zinc alloy and silicon. It is weakly diamagnetic and t his is interpreted as Pauli paramagnetism, which is overcompensated by the core diamagnetism. Its crystal structure has been determined from single-crystal diffractometer data: Fm3m, a = 1238.5(1) pm, Z = 4, R = 0.022 for 215 structure factors and 17 variable parameters. The Zr a nd Zn atoms occupy the positions of the Th and Mn atoms in Th6Mn23, wh ile the Si atoms are situated at octahedral voids of that structure fo rmed by the Zr atoms. Thus the atomic positions of Zr6Zn23Si correspon d to those of Sc11Ir4 (i.e. Sc6Sc16Ir7Ir). Various void positions of t hese structures correspond to hydrogen sites in previously reported ra re earth (R) transition metal (T) hydrides R(6)T(23)H(75-x).