Materials Data on Cu2Se by Materials Project

Abstract

Cu2Se crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are eight inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded in a 4-coordinate geometry to one Cu1+ and four Se2- atoms. The Cu–Cu bond length is 2.44 Å. There are a spread of Cu–Se bond distances ranging from 2.48–2.65 Å. In the second Cu1+ site, Cu1+ is bonded to four Se2- atoms to form distorted corner-sharing CuSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.39–2.65 Å. In the third Cu1+ site, Cu1+ is bonded to four Se2- atoms to form distorted corner-sharing CuSe4 tetrahedra. There are a spread of Cu–Se bond distances ranging from 2.39–2.68 Å. In the fourth Cu1+ site, Cu1+ is bonded in a trigonal planar geometry to three Se2- atoms. There are one shorter (2.39 Å) and two longer (2.42 Å) Cu–Se bond lengths. In the fifth Cu1+ site, Cu1+ is bonded to two equivalent Cu1+ and four Se2- atoms to form distorted CuCu2Se4 tetrahedra that share corners with seven CuSe4 tetrahedra and edges with two equivalent CuCu2Se4 tetrahedra. Both Cu–Cu bond lengths are 2.50 Å. There are a spread of Cu–Se bond distances ranging from 2.45–2.60 Å. In the sixth Cu1+ site, Cu1+ is bonded in a trigonal planar geometry to three Se2- atoms. There are one shorter (2.40 Å) and two longer (2.41 Å) Cu–Se bond lengths. In the seventh Cu1+ site, Cu1+ is bonded in a 9-coordinate geometry to three Cu1+ and six Se2- atoms. There are a spread of Cu–Se bond distances ranging from 2.86–3.01 Å. In the eighth Cu1+ site, Cu1+ is bonded in a trigonal planar geometry to three Se2- atoms. There are one shorter (2.41 Å) and two longer (2.43 Å) Cu–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 8-coordinate geometry to eight Cu1+ atoms. In the second Se2- site, Se2- is bonded to seven Cu1+ atoms to form a mixture of distorted edge and corner-sharing SeCu7 hexagonal pyramids. In the third Se2- site, Se2- is bonded in a 7-coordinate geometry to seven Cu1+ atoms. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to nine Cu1+ atoms.