Materials Data on Bi4PbS7 by Materials Project
PbBi4S7 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Pb2+ is bonded to seven S2- atoms to form distorted PbS7 pentagonal bipyramids that share corners with eight BiS6 octahedra, edges with four BiS6 octahedra, and faces with two equivalent PbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 24–69°. There are a spread of Pb–S bond distances ranging from 2.84–3.37 Å. There are four inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share corners with three BiS6 octahedra, corners with two equivalent PbS7 pentagonal bipyramids, and edges with five BiS6 octahedra. The corner-sharing octahedra tilt angles range from 10–56°. There are a spread of Bi–S bond distances ranging from 2.71–3.00 Å. In the second Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share corners with three BiS6 octahedra, corners with four equivalent PbS7 pentagonal bipyramids, edges with five BiS6 octahedra, and an edgeedge with one PbS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 10–48°. There are a spread of Bi–S bond distances ranging from 2.79–2.89 Å. In the third Bi3+ site, Bi3+ is bonded to six S2- atoms to form BiS6 octahedra that share corners with two BiS6 octahedra, corners with two equivalent PbS7 pentagonal bipyramids, edges with two equivalent BiS6 octahedra, and edges with three equivalent PbS7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 48–56°. There are a spread of Bi–S bond distances ranging from 2.75–2.87 Å. In the fourth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to seven S2- atoms. There are a spread of Bi–S bond distances ranging from 2.68–3.51 Å. There are seven inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to five Bi3+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Pb2+ and three Bi3+ atoms. In the third S2- site, S2- is bonded to four Bi3+ atoms to form distorted SBi4 trigonal pyramids that share corners with four equivalent SBi4Pb square pyramids, corners with two equivalent SBi4 trigonal pyramids, and an edgeedge with one SBi4Pb square pyramid. In the fourth S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Pb2+ and two Bi3+ atoms. In the fifth S2- site, S2- is bonded to one Pb2+ and four Bi3+ atoms to form distorted SBi4Pb square pyramids that share corners with four equivalent SBi4 trigonal pyramids, edges with two equivalent SBi4Pb square pyramids, and an edgeedge with one SBi4 trigonal pyramid. In the sixth S2- site, S2- is bonded in a 5-coordinate geometry to two equivalent Pb2+ and three Bi3+ atoms. In the seventh S2- site, S2- is bonded in a rectangular see-saw-like geometry to four Bi3+ atoms.