CsCuPSe3 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 11-coordinate geometry to one Cu(1), one Se(1), one Se(3), one Se(4), two equivalent Se(2), two equivalent Se(5), and three equivalent Se(6) atoms. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to one Cu(2), one Se(1), one Se(5), one Se(6), two equivalent Se(3), and two equivalent Se(4) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted trigonal planar geometry to one Cs(1), one Se(1), one Se(4), and one Se(6) atom. In the second Cu site, Cu(2) is bonded in a distorted trigonal planar geometry to one Cs(2), one Se(2), one Se(3), and one Se(5) atom. There are two inequivalent P sites. In the first P site, P(1) is bonded in a distorted tetrahedral geometry to one P(2), one Se(1), one Se(3), and one Se(4) atom. In the second P site, P(2) is bonded in a distorted tetrahedral geometry to one P(1), one Se(2), one Se(5), and one Se(6) atom. There are six inequivalent Se sites. In the first Se site, Se(3) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one Cu(2), and one P(1) atom. In the second Se site, Se(4) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one Cu(1), and one P(1) atom. In the third Se site, Se(5) is bonded in a distorted L-shaped geometry to one Cs(2), two equivalent Cs(1), one Cu(2), and one P(2) atom. In the fourth Se site, Se(6) is bonded in a 2-coordinate geometry to one Cs(2), three equivalent Cs(1), one Cu(1), and one P(2) atom. In the fifth Se site, Se(1) is bonded in a distorted L-shaped geometry to one Cs(1), one Cs(2), one Cu(1), and one P(1) atom. In the sixth Se site, Se(2) is bonded in a distorted L-shaped geometry to two equivalent Cs(1), one Cu(2), and one P(2) atom.
CsCuPSe3 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 11-coordinate geometry to one Cu(1), one Se(1), one Se(3), one Se(4), two equivalent Se(2), two equivalent Se(5), and three equivalent Se(6) atoms. The Cs(1)-Cu(1) bond length is 3.84 Å. The Cs(1)-Se(1) bond length is 3.76 Å. The Cs(1)-Se(3) bond length is 4.13 Å. The Cs(1)-Se(4) bond length is 4.00 Å. There is one shorter (3.84 Å) and one longer (3.95 Å) Cs(1)-Se(2) bond length. There is one shorter (3.90 Å) and one longer (4.13 Å) Cs(1)-Se(5) bond length. There are a spread of Cs(1)-Se(6) bond distances ranging from 3.88-4.11 Å. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to one Cu(2), one Se(1), one Se(5), one Se(6), two equivalent Se(3), and two equivalent Se(4) atoms. The Cs(2)-Cu(2) bond length is 3.70 Å. The Cs(2)-Se(1) bond length is 3.89 Å. The Cs(2)-Se(5) bond length is 3.96 Å. The Cs(2)-Se(6) bond length is 3.83 Å. There is one shorter (3.81 Å) and one longer (3.90 Å) Cs(2)-Se(3) bond length. There is one shorter (3.77 Å) and one longer (3.88 Å) Cs(2)-Se(4) bond length. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted trigonal planar geometry to one Cs(1), one Se(1), one Se(4), and one Se(6) atom. The Cu(1)-Se(1) bond length is 2.39 Å. The Cu(1)-Se(4) bond length is 2.39 Å. The Cu(1)-Se(6) bond length is 2.39 Å. In the second Cu site, Cu(2) is bonded in a distorted trigonal planar geometry to one Cs(2), one Se(2), one Se(3), and one Se(5) atom. The Cu(2)-Se(2) bond length is 2.40 Å. The Cu(2)-Se(3) bond length is 2.40 Å. The Cu(2)-Se(5) bond length is 2.39 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded in a distorted tetrahedral geometry to one P(2), one Se(1), one Se(3), and one Se(4) atom. The P(1)-P(2) bond length is 2.31 Å. The P(1)-Se(1) bond length is 2.22 Å. The P(1)-Se(3) bond length is 2.22 Å. The P(1)-Se(4) bond length is 2.22 Å. In the second P site, P(2) is bonded in a distorted tetrahedral geometry to one P(1), one Se(2), one Se(5), and one Se(6) atom. The P(2)-Se(2) bond length is 2.22 Å. The P(2)-Se(5) bond length is 2.21 Å. The P(2)-Se(6) bond length is 2.22 Å. There are six inequivalent Se sites. In the first Se site, Se(3) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one Cu(2), and one P(1) atom. In the second Se site, Se(4) is bonded in a 2-coordinate geometry to one Cs(1), two equivalent Cs(2), one Cu(1), and one P(1) atom. In the third Se site, Se(5) is bonded in a distorted L-shaped geometry to one Cs(2), two equivalent Cs(1), one Cu(2), and one P(2) atom. In the fourth Se site, Se(6) is bonded in a 2-coordinate geometry to one Cs(2), three equivalent Cs(1), one Cu(1), and one P(2) atom. In the fifth Se site, Se(1) is bonded in a distorted L-shaped geometry to one Cs(1), one Cs(2), one Cu(1), and one P(1) atom. In the sixth Se site, Se(2) is bonded in a distorted L-shaped geometry to two equivalent Cs(1), one Cu(2), and one P(2) atom.