Er4Cu5P7 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal I-42m space group. Er(1) is bonded in a 8-coordinate geometry to one Cu(3), one P(2), two equivalent P(3), and four equivalent P(1) atoms. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to four equivalent P(1) atoms to form a mixture of distorted corner and edge-sharing CuP4 tetrahedra. In the second Cu site, Cu(2) is bonded to four equivalent P(1) atoms to form a mixture of distorted corner and edge-sharing CuP4 tetrahedra. In the third Cu site, Cu(3) is bonded to four equivalent Er(1) and four equivalent P(3) atoms to form distorted corner-sharing CuEr4P4 hexagonal bipyramids. There are three inequivalent P sites. In the first P site, P(1) is bonded in a 8-coordinate geometry to four equivalent Er(1), two equivalent Cu(1), and two equivalent Cu(2) atoms. In the second P site, P(2) is bonded in a 8-coordinate geometry to four equivalent Er(1) and four equivalent P(3) atoms. In the third P site, P(3) is bonded in a 8-coordinate geometry to four equivalent Er(1), two equivalent Cu(3), and two equivalent P(2) atoms.
Er4Cu5P7 is Parent of FeAs superconductors-derived structured and crystallizes in the tetragonal I-42m space group. Er(1) is bonded in a 8-coordinate geometry to one Cu(3), one P(2), two equivalent P(3), and four equivalent P(1) atoms. The Er(1)-Cu(3) bond length is 2.93 Å. The Er(1)-P(2) bond length is 2.84 Å. Both Er(1)-P(3) bond lengths are 2.88 Å. There are two shorter (2.81 Å) and two longer (2.86 Å) Er(1)-P(1) bond lengths. There are three inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to four equivalent P(1) atoms to form a mixture of distorted corner and edge-sharing CuP4 tetrahedra. There are two shorter (2.38 Å) and two longer (2.43 Å) Cu(1)-P(1) bond lengths. In the second Cu site, Cu(2) is bonded to four equivalent P(1) atoms to form a mixture of distorted corner and edge-sharing CuP4 tetrahedra. All Cu(2)-P(1) bond lengths are 2.41 Å. In the third Cu site, Cu(3) is bonded to four equivalent Er(1) and four equivalent P(3) atoms to form distorted corner-sharing CuEr4P4 hexagonal bipyramids. All Cu(3)-P(3) bond lengths are 2.63 Å. There are three inequivalent P sites. In the first P site, P(1) is bonded in a 8-coordinate geometry to four equivalent Er(1), two equivalent Cu(1), and two equivalent Cu(2) atoms. In the second P site, P(2) is bonded in a 8-coordinate geometry to four equivalent Er(1) and four equivalent P(3) atoms. All P(2)-P(3) bond lengths are 2.63 Å. In the third P site, P(3) is bonded in a 8-coordinate geometry to four equivalent Er(1), two equivalent Cu(3), and two equivalent P(2) atoms.