Crystal structure and transport properties of Pd5HgSe

The Pd₅HgSe compound was synthesised by heating of stoichiometric mixture of elements at 400 °C by means of the evacuated silica glass tube technique. Its crystal structure was refined by Rietveld method from powder X-ray diffraction data. Pd₅HgSe adopts tetragonal symmetry, space group P4/mmm, unit cell parameters a = 4.0128(2) Å, c = 7.0378(6) Å, V = 113.33(2) Å³, Z = 1. The crystal structure of Pd₅HgSe is composed of alternating slabs of the AuCu₃-type cuboctahedra HgPd₁₂] and the PtHg₂-type rectangular prisms SePd₈]. The title compound crystallizes in the Pd₅TlAs structure type. The electric resistivity as well as the Seebeck coefficient measurements suggests semimetallic behaviour.