The crystal structure of the intermetallic compound ZrZn 22

A complete determination of the crystal structure of the binary intermetallic compound most rich in zinc, the ξ-phase, in the zirconium-zinc system has been carried out with use of all intensity data obtainable from single crystal Weissenberg photographs taken with Cu Kα radiation. The composition of the completely ordered phase is ZrZn_(22). The refinement of the structure was carried out by application of the method of least-squares. The space group is O_h^7-Fd3m with 184 atoms per unit cube. The edge of the cubic unit cell determined with use of powder samples was α_0 = 14.101 ± 0.002 A. The truncated tetrahedron, the icosahedron, and the hexagonal prism are prominent coordination polyhedra in this structure. An analysis of these polyhedra reveals that the packing of atoms around the crystallographically different zinc atoms varies widely.