Cu9Se5 crystallizes in the monoclinic C2 space group. There are five inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 4-coordinate geometry to one Se(2), one Se(3), and two equivalent Se(1) atoms. In the second Cu site, Cu(2) is bonded in a 7-coordinate geometry to one Cu(3), two equivalent Cu(5), one Se(1), one Se(2), and two equivalent Se(3) atoms. In the third Cu site, Cu(3) is bonded in a distorted trigonal planar geometry to one Cu(2), one Se(2), and two equivalent Se(1) atoms. In the fourth Cu site, Cu(4) is bonded in a distorted tetrahedral geometry to two equivalent Se(1) and two equivalent Se(3) atoms. In the fifth Cu site, Cu(5) is bonded in a distorted trigonal planar geometry to two equivalent Cu(2), one Se(1), and two equivalent Se(3) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(2), one Cu(4), one Cu(5), two equivalent Cu(1), and two equivalent Cu(3) atoms to form a mixture of distorted corner and edge-sharing SeCu7 hexagonal pyramids. In the second Se site, Se(2) is bonded in a distorted hexagonal planar geometry to two equivalent Cu(1), two equivalent Cu(2), and two equivalent Cu(3) atoms. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to one Cu(1), one Cu(4), two equivalent Cu(2), and two equivalent Cu(5) atoms.
Cu9Se5 crystallizes in the monoclinic C2 space group. There are five inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 4-coordinate geometry to one Se(2), one Se(3), and two equivalent Se(1) atoms. The Cu(1)-Se(2) bond length is 2.49 Å. The Cu(1)-Se(3) bond length is 2.44 Å. There is one shorter (2.45 Å) and one longer (2.65 Å) Cu(1)-Se(1) bond length. In the second Cu site, Cu(2) is bonded in a 7-coordinate geometry to one Cu(3), two equivalent Cu(5), one Se(1), one Se(2), and two equivalent Se(3) atoms. The Cu(2)-Cu(3) bond length is 2.56 Å. There is one shorter (2.51 Å) and one longer (2.59 Å) Cu(2)-Cu(5) bond length. The Cu(2)-Se(1) bond length is 2.70 Å. The Cu(2)-Se(2) bond length is 2.50 Å. There is one shorter (2.50 Å) and one longer (2.61 Å) Cu(2)-Se(3) bond length. In the third Cu site, Cu(3) is bonded in a distorted trigonal planar geometry to one Cu(2), one Se(2), and two equivalent Se(1) atoms. The Cu(3)-Se(2) bond length is 2.40 Å. There is one shorter (2.41 Å) and one longer (2.43 Å) Cu(3)-Se(1) bond length. In the fourth Cu site, Cu(4) is bonded in a distorted tetrahedral geometry to two equivalent Se(1) and two equivalent Se(3) atoms. Both Cu(4)-Se(1) bond lengths are 2.49 Å. Both Cu(4)-Se(3) bond lengths are 2.49 Å. In the fifth Cu site, Cu(5) is bonded in a distorted trigonal planar geometry to two equivalent Cu(2), one Se(1), and two equivalent Se(3) atoms. The Cu(5)-Se(1) bond length is 2.42 Å. There is one shorter (2.42 Å) and one longer (2.46 Å) Cu(5)-Se(3) bond length. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cu(2), one Cu(4), one Cu(5), two equivalent Cu(1), and two equivalent Cu(3) atoms to form a mixture of distorted corner and edge-sharing SeCu7 hexagonal pyramids. In the second Se site, Se(2) is bonded in a distorted hexagonal planar geometry to two equivalent Cu(1), two equivalent Cu(2), and two equivalent Cu(3) atoms. In the third Se site, Se(3) is bonded in a 6-coordinate geometry to one Cu(1), one Cu(4), two equivalent Cu(2), and two equivalent Cu(5) atoms.