Materials Data on HoCuPbSe3 by Materials Project
HoCuPbSe3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ho3+ is bonded to six Se2- atoms to form HoSe6 octahedra that share corners with two equivalent HoSe6 octahedra, corners with six equivalent PbSe7 pentagonal bipyramids, edges with two equivalent HoSe6 octahedra, edges with four equivalent PbSe7 pentagonal bipyramids, and edges with four equivalent CuSe4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Ho–Se bond distances ranging from 2.84–2.88 Å. Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with three equivalent PbSe7 pentagonal bipyramids, corners with two equivalent CuSe4 tetrahedra, edges with four equivalent HoSe6 octahedra, and edges with three equivalent PbSe7 pentagonal bipyramids. There are a spread of Cu–Se bond distances ranging from 2.44–2.52 Å. Pb2+ is bonded to seven Se2- atoms to form distorted PbSe7 pentagonal bipyramids that share corners with six equivalent HoSe6 octahedra, corners with three equivalent CuSe4 tetrahedra, edges with four equivalent HoSe6 octahedra, edges with two equivalent PbSe7 pentagonal bipyramids, edges with three equivalent CuSe4 tetrahedra, and faces with two equivalent PbSe7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 24–66°. There are a spread of Pb–Se bond distances ranging from 3.15–3.29 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ho3+, one Cu1+, and three equivalent Pb2+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ho3+, one Cu1+, and two equivalent Pb2+ atoms. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to two equivalent Ho3+, two equivalent Cu1+, and two equivalent Pb2+ atoms.