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

The new layered compound Ta₄Pd₃Te₁₆ resulted from an attempt to synthesize the hypothetical phase TaPdTe ₅. It crystallizes in space group I2/m(C_2h ³) 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 Ta ₄Pd₃Te₁₆ is closely related to Ta ₃Pd₃Te₁₄, but its electrical conductivity is considerably higher (σ₂₉₈ = 1.5 × 10⁴ vs. σ₂₉₇ = 2.2 × 10³Ω^-1 cm ^-1).