Ce(Au,Sb)2 with UHg2 structure type, a new member of the AlB2 family

A new ternary compound Ce(Au,Sb)2, with a homogeneity range has been observed from X-ray powder diffraction of as cast alloys, a = 4.743-4.712 Å, c = 3.567-3.768 Å. Its crystal structure was investigated by X-ray diffraction from Ce(Au1−xSbx)2 (x = 0.266) single crystal: CAD-4 automatic diffractometer, Mo Kα radiation, a = 4.7256(6) Å, c = 3.6711(6) Å, P6/mmm space group, V = 70.997(17) Å3, Z = 1, ρ = 10.732 Mg/m3, μ = 76.369 mm−1, R1 = 0.0415, wR2 = 0.0793 for 99 reflections with I > 2σ(I0). The coordination polyhedron of X (X = 0.734Au + 0.266Sb) atom is a full-capped trigonal prism [XCe6X3X2]. Ce atom is coordinated by 14 atoms: [CeX12Ce2]. The compound is isotypic with UHg2 structure, a deformation derivative of AlB2 structure type. It forms isostructural compounds with La and Pr.