Redetermination of dysprosium trinickel from single-crystal X-ray data

The crystal structure of the title compound, DyNi₃, was redetermined from single-crystal X-ray diffraction data. In comparison with previous studies based on powder X-ray diffraction data [Lemaire & Paccard (1969). Bull. Soc. Fr. Minéral. Cristallogr. 92, 9-16; Tsai et al. (1974). J. Appl. Phys. 45, 3582-3586], the present redetermination revealed refined coordinates and anisotropic displacement parameters for all atoms. The crystal structure of DyNi₃ adopts the PuNi₃ structure type and can be derived from the CaCu₅ structure type as an inter­growth structure. The asymmetric unit contains two Dy sites (site symmetries 3m and -3) and three Ni sites (m, 3m and -3m). The two different coordination polyhedra of Dy are a Frank-Kasper polyhedron formed by four Dy and 12 Ni atoms and a pseudo-Frank-Kasper polyhedron formed by two Dy and 18 Ni atoms. The three different coordination polyhedra of Ni are Frank-Kasper icosa­hedra formed by five Dy and seven Ni atoms, three Dy and nine Ni atoms, and six Dy and six Ni atoms.