Crystal structure, chemical bonding and magnetic properties of the new antimonides Ce₂Ir₃Sb₄, La₂Ir₃Sb₄, and Ce₂Rh₃Sb₄

Abstract

Abstract The antimonides Ce 2 Ir 3 Sb 4 , La 2 Ir 3 Sb 4 , and Ce 2 Rh 3 Sb 4 were synthesized by solid state reaction from the elements. The crystal structures of these compounds were determined from single crystal X-ray diffraction data. Ce 2 Ir 3 Sb 4 crystallises in a new structure type in the space group Pnma (no. 62) with a = 16.1510(8) Å, b = 4.5600(3) Å, c = 10.9463(5) Å. La 2 Ir 3 Sb 4 and Ce 2 Rh 3 Sb 4 crystallise in the Ce 2 Ir 3 Sb 4 structure type as well with a = 16.2659(10) Å, b = 4.5896(3) Å, c = 10.9996(7) Å) and a = 16.2293(8) Å, b = 4.5604(2) Å, c = 10.9804(5) Å, respectively. The four- and five-bonded transition metal atoms and three- and four-bounded Sb atoms form a 3D-network with the rare-earth metal embedded in its cavities, resembling the topology of Ca in the CaBe 2 Ge 2 or Th in ThCr 2 Si 2 type. Magnetic susceptibility and X-ray absorption near edge spectroscopy data indicate a stable trivalent state for Ce in the Ce 2 Ir 3 Sb 4 compound.