Rb2Cu2Sb2S5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one S(4), three equivalent S(1), and three equivalent S(2) atoms. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one S(4), three equivalent S(5), and four equivalent S(3) atoms. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(2), one S(3), and two equivalent S(4) atoms to form corner-sharing CuS4 tetrahedra. In the second Cu site, Cu(2) is bonded in a 3-coordinate geometry to one Sb(2), one S(2), and two equivalent S(1) atoms. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a distorted trigonal non-coplanar geometry to one S(1), one S(2), and one S(4) atom. In the second Sb site, Sb(2) is bonded in a 4-coordinate geometry to one Cu(2), one S(3), and two equivalent S(5) atoms. There are five inequivalent S sites. In the first S site, S(3) is bonded in a 6-coordinate geometry to four equivalent Rb(2), one Cu(1), and one Sb(2) atom. In the second S site, S(4) is bonded to one Rb(1), one Rb(2), two equivalent Cu(1), and one Sb(1) atom to form corner-sharing SRb2Cu2Sb trigonal bipyramids. In the third S site, S(5) is bonded in a 5-coordinate geometry to three equivalent Rb(2) and two equivalent Sb(2) atoms. In the fourth S site, S(1) is bonded in a 6-coordinate geometry to three equivalent Rb(1), two equivalent Cu(2), and one Sb(1) atom. In the fifth S site, S(2) is bonded in a 6-coordinate geometry to three equivalent Rb(1), one Cu(1), one Cu(2), and one Sb(1) atom.
Rb2Cu2Sb2S5 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 7-coordinate geometry to one S(4), three equivalent S(1), and three equivalent S(2) atoms. The Rb(1)-S(4) bond length is 3.29 Å. There are a spread of Rb(1)-S(1) bond distances ranging from 3.44-3.46 Å. There are a spread of Rb(1)-S(2) bond distances ranging from 3.35-3.75 Å. In the second Rb site, Rb(2) is bonded in a 8-coordinate geometry to one S(4), three equivalent S(5), and four equivalent S(3) atoms. The Rb(2)-S(4) bond length is 3.37 Å. There are a spread of Rb(2)-S(5) bond distances ranging from 3.40-3.62 Å. There are a spread of Rb(2)-S(3) bond distances ranging from 3.48-3.64 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded to one S(2), one S(3), and two equivalent S(4) atoms to form corner-sharing CuS4 tetrahedra. The Cu(1)-S(2) bond length is 2.43 Å. The Cu(1)-S(3) bond length is 2.40 Å. There is one shorter (2.36 Å) and one longer (2.37 Å) Cu(1)-S(4) bond length. In the second Cu site, Cu(2) is bonded in a 3-coordinate geometry to one Sb(2), one S(2), and two equivalent S(1) atoms. The Cu(2)-Sb(2) bond length is 2.84 Å. The Cu(2)-S(2) bond length is 2.29 Å. There is one shorter (2.30 Å) and one longer (2.35 Å) Cu(2)-S(1) bond length. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded in a distorted trigonal non-coplanar geometry to one S(1), one S(2), and one S(4) atom. The Sb(1)-S(1) bond length is 2.52 Å. The Sb(1)-S(2) bond length is 2.47 Å. The Sb(1)-S(4) bond length is 2.45 Å. In the second Sb site, Sb(2) is bonded in a 4-coordinate geometry to one Cu(2), one S(3), and two equivalent S(5) atoms. The Sb(2)-S(3) bond length is 2.40 Å. There is one shorter (2.49 Å) and one longer (2.55 Å) Sb(2)-S(5) bond length. There are five inequivalent S sites. In the first S site, S(3) is bonded in a 6-coordinate geometry to four equivalent Rb(2), one Cu(1), and one Sb(2) atom. In the second S site, S(4) is bonded to one Rb(1), one Rb(2), two equivalent Cu(1), and one Sb(1) atom to form corner-sharing SRb2Cu2Sb trigonal bipyramids. In the third S site, S(5) is bonded in a 5-coordinate geometry to three equivalent Rb(2) and two equivalent Sb(2) atoms. In the fourth S site, S(1) is bonded in a 6-coordinate geometry to three equivalent Rb(1), two equivalent Cu(2), and one Sb(1) atom. In the fifth S site, S(2) is bonded in a 6-coordinate geometry to three equivalent Rb(1), one Cu(1), one Cu(2), and one Sb(1) atom.