Synthesis, crystal structure and electrical conductivity of a new layered ternary telluride Ta4Pd3Te16

Abstract

The new layered compound Ta₄Pd₃Te₁₆ resulted from an attempt to synthesize the hypothetical phase TaPdTe₅. It crystallizes in space group I2/m(C_2h³) of the monoclinic system with two formula units in a cell of dimensions a= 17.687(4), b= 3.735(1), c= 19.510(4)Å and β= 110.42(1)°(T= 111 K). The layers consist of bicapped trigonal prismatic Ta atoms, octahedral Ta atoms and octahedral Pd atoms co-ordinated by Te atoms. Structurally Ta₄Pd₃Te₁₆ is closely related to Ta₃Pd₃Te₁₄, but its electrical conductivity is considerably higher (σ₂₉₈= 1.5 × 10⁴vs.σ₂₉₇= 2.2 × 10³Ω^–1 cm^–1).