Synthesis and Characterization of Ba₃Bi_6.67Se₁₃ and Its Filled Variants Ba₃Bi₆PbSe₁₃ and Ba₃Bi₆SnSe₁₃

Abstract

The three title compounds were synthesized at 710 °C and their structure type is isotypic to Sr4Bi6Se13 and β-K2Bi8Se13. The compounds crystallize in P21/m (Z = 2) with a = 17.2228(6) Å, b = 4.2729(1) Å, c = 18.4659(6) Å, β = 90.720(0)° for Ba3Bi6.67Se13; a = 17.2427(4) Å, b = 4.2736(1) Å, c = 18.4560(4) Å, β = 90.861(1)° for Ba3Bi6PbSe13; and a = 17.2498(5) Å, b = 4.2912(1) Å, c = 18.4590(5) Å, and β = 90.679(1)° for Ba3Bi6SnSe13. The coordination environments of Bi/Pb/Sn are distorted Se octahedra, while the coordination spheres of Ba are bi- or tricapped trigonal prisms. Transport measurements indicate that Ba3Bi6.67Se13 and Ba3Bi6PbSe13 are semiconducting