DOE OSTI2020
Li5(Cu2P3)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. there are three inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to eight equivalent P+1.67- atoms to form LiP8 hexagonal bipyramids that share corners with sixteen equivalent CuP4 tetrahedra, edges with four equivalent LiP6 pentagonal pyramids, edges with four equivalent CuP4 tetrahedra, and faces with two equivalent LiP8 hexagonal bipyramids. All Li–P bond lengths are 2.89 Å. In the second Li1+ site, Li1+ is bonded in a distorted hexagonal planar geometry to six P+1.67- atoms. There are two shorter (2.60 Å) and four longer (2.75 Å) Li–P bond lengths. In the third Li1+ site, Li1+ is bonded to six P+1.67- atoms to form distorted LiP6 pentagonal pyramids that share corners with six equivalent CuP4 tetrahedra, edges with two equivalent LiP8 hexagonal bipyramids, edges with four equivalent LiP6 pentagonal pyramids, edges with four equivalent CuP4 tetrahedra, and a faceface with one LiP6 pentagonal pyramid. There are two shorter (2.57 Å) and four longer (2.67 Å) Li–P bond lengths. Cu+1.25+ is bonded to four P+1.67- atoms to form CuP4 tetrahedra that share corners with four equivalent LiP8 hexagonal bipyramids, corners with three equivalent LiP6 pentagonal pyramids, corners with three equivalent CuP4 tetrahedra, an edgeedge with one LiP8 hexagonal bipyramid, edges with two equivalent LiP6 pentagonal pyramids, and edges with two equivalent CuP4 tetrahedra. There are a spread of Cu–P bond distances ranging from 2.31–2.46 Å. There are two inequivalent P+1.67- sites. In the first P+1.67- site, P+1.67- is bonded in a 9-coordinate geometry to five Li1+, three equivalent Cu+1.25+, and one P+1.67- atom. The P–P bond length is 2.17 Å. In the second P+1.67- site, P+1.67- is bonded in a 9-coordinate geometry to six Li1+, two equivalent Cu+1.25+, and one P+1.67- atom. The P–P bond length is 2.17 Å.