DOE OSTI2020
In2Pb4Bi4Se13 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. there are three inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four Se2- atoms to form InSe4 tetrahedra that share corners with four BiSe6 octahedra and corners with two equivalent InSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 72–74°. There are a spread of In–Se bond distances ranging from 2.61–2.67 Å. In the second In3+ site, In3+ is bonded to six Se2- atoms to form InSe6 octahedra that share corners with four equivalent BiSe6 octahedra, edges with two equivalent InSe6 octahedra, and edges with six BiSe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are two shorter (2.68 Å) and four longer (2.90 Å) In–Se bond lengths. In the third In3+ site, In3+ is bonded to six Se2- atoms to form InSe6 octahedra that share corners with four equivalent BiSe6 octahedra, corners with four equivalent PbSe7 pentagonal bipyramids, edges with two equivalent InSe6 octahedra, and edges with six BiSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are two shorter (2.69 Å) and four longer (2.89 Å) In–Se bond lengths. There are four inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Pb–Se bond distances ranging from 3.10–3.69 Å. In the second Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Pb–Se bond distances ranging from 3.11–3.61 Å. In the third Pb2+ site, Pb2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Pb–Se bond distances ranging from 3.17–3.57 Å. In the fourth Pb2+ site, Pb2+ is bonded to seven Se2- atoms to form distorted PbSe7 pentagonal bipyramids that share corners with two equivalent InSe6 octahedra, corners with six BiSe6 octahedra, edges with four BiSe6 octahedra, and faces with two equivalent PbSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 7–69°. There are a spread of Pb–Se bond distances ranging from 2.97–3.47 Å. There are four inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share a cornercorner with one BiSe6 octahedra, corners with two equivalent PbSe7 pentagonal bipyramids, corners with two equivalent InSe4 tetrahedra, edges with two equivalent InSe6 octahedra, edges with four BiSe6 octahedra, and an edgeedge with one PbSe7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 57°. There are a spread of Bi–Se bond distances ranging from 2.90–3.10 Å. In the second Bi3+ site, Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share corners with two equivalent InSe6 octahedra, corners with two equivalent PbSe7 pentagonal bipyramids, an edgeedge with one InSe6 octahedra, and edges with four BiSe6 octahedra. The corner-sharing octahedral tilt angles are 5°. There are a spread of Bi–Se bond distances ranging from 2.82–3.18 Å. In the third Bi3+ site, Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share corners with two equivalent InSe6 octahedra, an edgeedge with one InSe6 octahedra, edges with four BiSe6 octahedra, and edges with two equivalent PbSe7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 6°. There are a spread of Bi–Se bond distances ranging from 2.83–3.20 Å. In the fourth Bi3+ site, Bi3+ is bonded to six Se2- atoms to form BiSe6 octahedra that share a cornercorner with one BiSe6 octahedra, corners with two equivalent PbSe7 pentagonal bipyramids, corners with two equivalent InSe4 tetrahedra, edges with two equivalent InSe6 octahedra, edges with four BiSe6 octahedra, and an edgeedge with one PbSe7 pentagonal bipyramid. The corner-sharing octahedral tilt angles are 57°. There are a spread of Bi–Se bond distances ranging from 2.84–3.21 Å. There are thirteen inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 2-coordinate geometry to three Pb2+ and two equivalent Bi3+ atoms. In the second Se2- site, Se2- is bonded to four Pb2+ and one Bi3+ atom to form distorted SeBiPb4 trigonal bipyramids that share corners with four SeBi3Pb2 square pyramids, an edgeedge with one SeBi3Pb2 square pyramid, and edges with two equivalent SeBiPb4 trigonal bipyramids. In the third Se2- site, Se2- is bonded to two equivalent In3+, one Pb2+, and three Bi3+ atoms to form distorted SeIn2Bi3Pb square pyramids that share corners with two equivalent SeIn2Bi3Pb square pyramids, a cornercorner with one SeIn2Bi2 tetrahedra, and edges with seven SeBi3Pb2 square pyramids. In the fourth Se2- site, Se2- is bonded in a 2-coordinate geometry to three Pb2+ and two equivalent Bi3+ atoms. In the fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to two equivalent Pb2+ and three Bi3+ atoms. In the sixth Se2- site, Se2- is bonded in a 1-coordinate geometry to one In3+, two equivalent Pb2+, and two equivalent Bi3+ atoms. In the seventh Se2- site, Se2- is bonded in a distorted single-bond geometry to one In3+ and four Pb2+ atoms. In the eighth Se2- site, Se2- is bonded in a distorted single-bond geometry to one In3+ and four Pb2+ atoms. In the ninth Se2- site, Se2- is bonded to two equivalent Pb2+ and three Bi3+ atoms to form distorted SeBi3Pb2 square pyramids that share a cornercorner with one SeBiPb4 square pyramid, corners with two equivalent SeIn2Bi2 tetrahedra, corners with two equivalent SeBiPb4 trigonal bipyramids, edges with four SeBi3Pb2 square pyramids, and an edgeedge with one SeBiPb4 trigonal bipyramid. In the tenth Se2- site, Se2- is bonded to four Pb2+ and one Bi3+ atom to form distorted SeBiPb4 square pyramids that share a cornercorner with one SeBi3Pb2 square pyramid and edges with four SeBiPb4 square pyramids. In the eleventh Se2- site, Se2- is bonded to two equivalent In3+ and three Bi3+ atoms to form SeIn2Bi3 square pyramids that share corners with two equivalent SeIn2Bi3 square pyramids, a cornercorner with one SeIn2Bi2 tetrahedra, corners with two equivalent SeBiPb4 trigonal bipyramids, and edges with three equivalent SeIn2Bi3 square pyramids. In the twelfth Se2- site, Se2- is bonded to two equivalent In3+ and two Bi3+ atoms to form distorted SeIn2Bi2 tetrahedra that share corners with four SeBi3Pb2 square pyramids and corners with two equivalent SeIn2Bi2 tetrahedra. In the thirteenth Se2- site, Se2- is bonded in a 5-coordinate geometry to one In3+, two equivalent Pb2+, and two equivalent Bi3+ atoms.