Materials Data on Er4Cu5P7 by Materials Project

Er4Cu5P7 crystallizes in the tetragonal I-42m space group. The structure is three-dimensional. Er3+ is bonded to seven P3- atoms to form distorted ErP7 pentagonal bipyramids that share corners with six equivalent ErP7 pentagonal bipyramids, corners with eight CuP4 tetrahedra, edges with three equivalent ErP7 pentagonal bipyramids, edges with four CuP4 tetrahedra, and faces with three equivalent ErP7 pentagonal bipyramids. There are a spread of Er–P bond distances ranging from 2.81–2.88 Å. There are three inequivalent Cu+1.80+ sites. In the first Cu+1.80+ site, Cu+1.80+ is bonded to four equivalent P3- atoms to form CuP4 tetrahedra that share corners with eight equivalent ErP7 pentagonal bipyramids, corners with four equivalent CuP4 tetrahedra, edges with four equivalent ErP7 pentagonal bipyramids, and edges with four equivalent CuP4 tetrahedra. There are two shorter (2.38 Å) and two longer (2.43 Å) Cu–P bond lengths. In the second Cu+1.80+ site, Cu+1.80+ is bonded to four equivalent P3- atoms to form CuP4 tetrahedra that share corners with eight equivalent ErP7 pentagonal bipyramids, corners with four equivalent CuP4 tetrahedra, edges with four equivalent ErP7 pentagonal bipyramids, and edges with four equivalent CuP4 tetrahedra. All Cu–P bond lengths are 2.41 Å. In the third Cu+1.80+ site, Cu+1.80+ is bonded in a square co-planar geometry to four equivalent P3- atoms. All Cu–P bond lengths are 2.63 Å. There are three inequivalent P3- sites. In the first P3- site, P3- is bonded in a 8-coordinate geometry to four equivalent Er3+ and four Cu+1.80+ atoms. In the second P3- site, P3- is bonded in a 8-coordinate geometry to four equivalent Er3+ and four equivalent P3- atoms. All P–P bond lengths are 2.63 Å. In the third P3- site, P3- is bonded in a 8-coordinate geometry to four equivalent Er3+, two equivalent Cu+1.80+, and two equivalent P3- atoms.