Cd₁₃-_xin_ySb₁₀ (x≈ 2.7, y≈1.5): An interstitial-free variant of thermoelectric ß-Zn ₄Sb₃

Cd_13-x;In₇Sb₁₀ (x≈2.7, Y≈ 1.5) was synthesized in the form of millsized crystals from reaction mixtures containing excess cadmium. The intermetallic compound crystallizes in the rhombohedral space group R3m with α = 12.9704(4), c= 12.9443(5) Å, V= 1886.0(1) Å₃, Z=3 and is isostructural to thermoelectric ß-Zn ₄Sb₃ and ßCd₄Sb₃. However, in contrast to these last two compounds Cd_13-xIn_ySb ₁₀ is free from interstitial atoms and does not display any temperature polymorphism. The electrical resistivity of Cd_13-xIn _ySb₁₀ is considerably higher than that of Zn ₄Sb₃ and Cd₄Sb₃ although the temperature behavior remains that of a metal. The thermal conductivity of Cd_13-xIn_ySb₁₀ is low, with room-temperature magnitudes around 0.8Wm^-1K^-1, which is comparable to disordered or complex structured Cd₄Sb₃ and Zn ₄Sb₃.