Materials Data on TmCuPbSe3 by Materials Project
TmCuPbSe3 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent Tm3+ sites. In the first Tm3+ site, Tm3+ is bonded to six Se2- atoms to form TmSe6 octahedra that share corners with two equivalent TmSe6 octahedra, edges with two equivalent TmSe6 octahedra, and edges with four CuSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 43–45°. There are a spread of Tm–Se bond distances ranging from 2.84–2.88 Å. In the second Tm3+ site, Tm3+ is bonded to six Se2- atoms to form TmSe6 octahedra that share corners with two equivalent TmSe6 octahedra, edges with two equivalent TmSe6 octahedra, and edges with four CuSe4 tetrahedra. The corner-sharing octahedra tilt angles range from 43–45°. There are a spread of Tm–Se bond distances ranging from 2.84–2.86 Å. There are two inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with two equivalent CuSe4 tetrahedra and edges with four TmSe6 octahedra. There are two shorter (2.46 Å) and two longer (2.52 Å) Cu–Se bond lengths. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form CuSe4 tetrahedra that share corners with two equivalent CuSe4 tetrahedra and edges with four TmSe6 octahedra. There are a spread of Cu–Se bond distances ranging from 2.46–2.52 Å. There are two inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to eight Se2- atoms. There are a spread of Pb–Se bond distances ranging from 3.10–3.78 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 3.10–3.69 Å. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Tm3+, one Cu1+, and three Pb2+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Tm3+, one Cu1+, and three Pb2+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Tm3+, one Cu1+, and three Pb2+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Tm3+, one Cu1+, and three Pb2+ atoms. In the fifth Se2- site, Se2- is bonded in a 6-coordinate geometry to two Tm3+, two equivalent Cu1+, and two equivalent Pb2+ atoms. In the sixth Se2- site, Se2- is bonded in a 6-coordinate geometry to two Tm3+, two equivalent Cu1+, and two equivalent Pb2+ atoms.