Redetermination of the crystal structure of RhPb from single-crystal X-ray diffraction data, revealing a rhodium deficiency.

RhPb (rhodium dilead) is a superconductor crystallizing in the CuAl structure type (space group 4/). The Rh and Pb atoms are located at the 4 (site symmetry 422) and 8 (.2) sites, respectively. The crystal structure is composed of [RhPb] anti-prisms, which share their square faces along the axis and the edges in the direction perpendicular to the axis. We have succeeded in growing single crystals of RhPb and have re-determined the crystal structure on basis of single-crystal X-ray diffraction data. In comparison with the previous structure studies using powder X-ray diffraction data [Wallbaum (1943 ▸). . , 218-221; Havinga (1972 ▸). , 169-186], the current structure analysis of RhPb leads to more precise unit-cell parameters and fractional coordinates, together with anisotropic displacement parameters for the two atoms. In addition and likewise different from the previous studies, we have found a slight deficiency of Rh in RhPb, leading to a refined formula of RhPb.