The crystal structure of Pd₃HgTe₃, the synthetic analogue of temagamite

The crystal structure of the synthetic analogue of the mineral temagamite, Pd₃HgTe₃, was solved and refined to an R-factor of 0.0522 from single-crystal X-ray diffraction data. The structure is trigonal, space group P3m1, with a = 7.8211(6) Å, c = 17.281(1) Å, V = 917.8(1) ų (hexagonal setting) and Z = 6. Layer modules (A–F) stacked along the c-axis form the crystal structure of Pd₃HgTe₃. Module A is composed of isolated octahedra [PdTe₆], which share faces with adjacent octahedra from neighbouring modules. The edge-sharing [PdTe₆] octahedra and [PdTe₄] squares form the modules B and F, whereas the corner-sharing [PdTe₄] squares constitute modules C, D and E. The Hg atoms occupy the anti-cubooctahedral voids formed by Te atoms. The Pd–Pd and Pd–Hg bonds are also present in the structure. The symmetry of temagamite was revised based on the structural results of this study.