PREPARATION AND CRYSTAL-STRUCTURE OF CA5Z N3

Ca5Zn3 has been synthesized from stoichiometric amounts of the pure el ements. It crystallizes with the Cr5B5 type of structure: space group I4/mcm, a = 796.3(2), c = 1540.7(3) pm, c/a = 1.93, Z = 4, R = 4.05% ( all F(o)), 3.93% (F(o) greater-than-or-equal-to 2simga (F(o))). Around one central calcium atom distorted rhombic dodecahedra occur which co ntain all the remaining calcium atoms and all zinc atoms. They build u p a three dimensional infinite network. In the tetragonal a-a-plane th e rhombic dodecahedra are interconnected as well via common faces as v ia Zn-Zn dumbbells (Zn-Zn 263 pm), along [001] they share common zinc atoms.