The crystal structure of Ce2Ni7

Abstract

The structure detn. of Ce2Ni7 is described. The unit cell is hexagonal, probable space group P63/mmc, with a = 4.98 0.02, c = 24.52 0.08 A., and contains 4 formula units. The structure consists of double layers of the CeNi5 structure (CaCu5 type) alternating with double layers of the CeNi2 structure (Cu2Mg type). Relations among this structure, the CeNi3, and PuNi3 structures, the fundamental MX5 structure, and the 3 Laves or Friauf phases are discussed in detail.