Materials Data on AgSb(Te8Pb7)2 by Materials Project

Abstract

AgSb(Pb7Te8)2 is alpha Po-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ag1+ is bonded to six Te2- atoms to form AgTe6 octahedra that share corners with two equivalent PbTe6 octahedra, corners with four equivalent SbTe6 octahedra, and edges with twelve PbTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.98 Å) and four longer (3.36 Å) Ag–Te bond lengths. There are four inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded to six Te2- atoms to form a mixture of edge and corner-sharing PbTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (3.22 Å) and four longer (3.27 Å) Pb–Te bond lengths. In the second Pb2+ site, Pb2+ is bonded to six Te2- atoms to form PbTe6 octahedra that share corners with six PbTe6 octahedra, edges with two equivalent AgTe6 octahedra, edges with two equivalent SbTe6 octahedra, and edges with eight equivalent PbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (3.23 Å) and four longer (3.27 Å) Pb–Te bond lengths. In the third Pb2+ site, Pb2+ is bonded to six Te2- atoms to form PbTe6 octahedra that share corners with six equivalent PbTe6 octahedra, an edgeedge with one AgTe6 octahedra, an edgeedge with one SbTe6 octahedra, and edges with ten PbTe6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Pb–Te bond distances ranging from 3.20–3.28 Å. In the fourth Pb2+ site, Pb2+ is bonded to six Te2- atoms to form PbTe6 octahedra that share a cornercorner with one AgTe6 octahedra, a cornercorner with one SbTe6 octahedra, corners with four equivalent PbTe6 octahedra, and edges with twelve PbTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (3.27 Å) and two longer (3.40 Å) Pb–Te bond lengths. Sb3+ is bonded to six Te2- atoms to form SbTe6 octahedra that share corners with two equivalent PbTe6 octahedra, corners with four equivalent AgTe6 octahedra, and edges with twelve PbTe6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (3.11 Å) and four longer (3.17 Å) Sb–Te bond lengths. There are six inequivalent Te2- sites. In the first Te2- site, Te2- is bonded to six Pb2+ atoms to form a mixture of edge and corner-sharing TePb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the second Te2- site, Te2- is bonded to six Pb2+ atoms to form a mixture of edge and corner-sharing TePb6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the third Te2- site, Te2- is bonded to one Ag1+, four Pb2+, and one Sb3+ atom to form TeAgSbPb4 octahedra that share corners with six TePb6 octahedra and edges with twelve TeAgSbPb4 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the fourth Te2- site, Te2- is bonded to one Ag1+ and five Pb2+ atoms to form TeAgPb5 octahedra that share corners with six TeAgPb5 octahedra and edges with twelve TePb6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the fifth Te2- site, Te2- is bonded to five Pb2+ and one Sb3+ atom to form TeSbPb5 octahedra that share corners with six TeAgPb5 octahedra and edges with twelve TePb6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the sixth Te2- site, Te2- is bonded to one Ag1+, four Pb2+, and one Sb3+ atom to form TeAgSbPb4 octahedra that share corners with six TePb6 octahedra and edges with twelve TeAgSbPb4 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. Both Te–Pb bond lengths are 3.20 Å.