Cs4(BSe)9 crystallizes in the triclinic P-1 space group. There are four inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to one B(8), one B(9), one Se(3), one Se(6), one Se(8), one Se(9), two equivalent Se(2), and two equivalent Se(7) atoms. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to one B(7), one B(8), one Se(1), one Se(3), one Se(4), one Se(5), one Se(7), one Se(9), and two equivalent Se(8) atoms. In the third Cs site, Cs(3) is bonded in a 8-coordinate geometry to one Se(1), one Se(4), one Se(6), one Se(8), two equivalent Se(7), and two equivalent Se(9) atoms. In the fourth Cs site, Cs(4) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), one Se(4), one Se(7), one Se(8), one Se(9), and two equivalent Se(5) atoms. There are nine inequivalent B sites. In the first B site, B(1) is bonded in a distorted single-bond geometry to one B(2), one B(3), one B(4), one B(5), one B(6), and one Se(1) atom. In the second B site, B(2) is bonded in a 6-coordinate geometry to one B(1), one B(3), one B(4), one B(5), one B(6), and one Se(2) atom. In the third B site, B(3) is bonded in a distorted single-bond geometry to one B(1), one B(2), one B(4), one B(5), one B(6), and one Se(3) atom. In the fourth B site, B(4) is bonded in a 6-coordinate geometry to one B(1), one B(2), one B(3), one B(5), one B(6), and one Se(4) atom. In the fifth B site, B(5) is bonded in a 6-coordinate geometry to one B(1), one B(2), one B(3), one B(4), one B(6), and one Se(5) atom. In the sixth B site, B(6) is bonded in a distorted single-bond geometry to one B(1), one B(2), one B(3), one B(4), one B(5), and one Se(6) atom. In the seventh B site, B(7) is bonded in a trigonal planar geometry to one Cs(2), one Se(1), one Se(2), and one Se(7) atom. In the eighth B site, B(8) is bonded in a trigonal planar geometry to one Cs(1), one Cs(2), one Se(3), one Se(4), and one Se(8) atom. In the ninth B site, B(9) is bonded in a trigonal planar geometry to one Cs(1), one Se(5), one Se(6), and one Se(9) atom. There are nine inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted water-like geometry to one Cs(2), one Cs(3), one Cs(4), one B(1), and one B(7) atom. In the second Se site, Se(2) is bonded in a distorted water-like geometry to one Cs(4), two equivalent Cs(1), one B(2), and one B(7) atom. In the third Se site, Se(3) is bonded in a distorted L-shaped geometry to one Cs(1), one Cs(2), one B(3), and one B(8) atom. In the fourth Se site, Se(4) is bonded in a distorted water-like geometry to one Cs(2), one Cs(3), one Cs(4), one B(4), and one B(8) atom. In the fifth Se site, Se(5) is bonded in a distorted water-like geometry to one Cs(2), two equivalent Cs(4), one B(5), and one B(9) atom. In the sixth Se site, Se(6) is bonded in a distorted water-like geometry to one Cs(1), one Cs(3), one B(6), and one B(9) atom. In the seventh Se site, Se(7) is bonded in a distorted single-bond geometry to one Cs(2), one Cs(4), two equivalent Cs(1), two equivalent Cs(3), and one B(7) atom. In the eighth Se site, Se(8) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), one Cs(4), two equivalent Cs(2), and one B(8) atom. In the ninth Se site, Se(9) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(2), one Cs(4), two equivalent Cs(3), and one B(9) atom.
Cs4(BSe)9 crystallizes in the triclinic P-1 space group. There are four inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to one B(8), one B(9), one Se(3), one Se(6), one Se(8), one Se(9), two equivalent Se(2), and two equivalent Se(7) atoms. The Cs(1)-B(8) bond length is 3.82 Å. The Cs(1)-B(9) bond length is 3.93 Å. The Cs(1)-Se(3) bond length is 3.82 Å. The Cs(1)-Se(6) bond length is 3.71 Å. The Cs(1)-Se(8) bond length is 3.84 Å. The Cs(1)-Se(9) bond length is 4.02 Å. There is one shorter (4.06 Å) and one longer (4.10 Å) Cs(1)-Se(2) bond length. There is one shorter (3.76 Å) and one longer (3.88 Å) Cs(1)-Se(7) bond length. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to one B(7), one B(8), one Se(1), one Se(3), one Se(4), one Se(5), one Se(7), one Se(9), and two equivalent Se(8) atoms. The Cs(2)-B(7) bond length is 3.91 Å. The Cs(2)-B(8) bond length is 3.74 Å. The Cs(2)-Se(1) bond length is 3.75 Å. The Cs(2)-Se(3) bond length is 3.68 Å. The Cs(2)-Se(4) bond length is 3.94 Å. The Cs(2)-Se(5) bond length is 3.92 Å. The Cs(2)-Se(7) bond length is 4.05 Å. The Cs(2)-Se(9) bond length is 3.74 Å. There is one shorter (3.74 Å) and one longer (3.81 Å) Cs(2)-Se(8) bond length. In the third Cs site, Cs(3) is bonded in a 8-coordinate geometry to one Se(1), one Se(4), one Se(6), one Se(8), two equivalent Se(7), and two equivalent Se(9) atoms. The Cs(3)-Se(1) bond length is 4.03 Å. The Cs(3)-Se(4) bond length is 4.03 Å. The Cs(3)-Se(6) bond length is 3.78 Å. The Cs(3)-Se(8) bond length is 3.64 Å. There is one shorter (3.82 Å) and one longer (4.04 Å) Cs(3)-Se(7) bond length. There is one shorter (3.78 Å) and one longer (4.11 Å) Cs(3)-Se(9) bond length. In the fourth Cs site, Cs(4) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), one Se(4), one Se(7), one Se(8), one Se(9), and two equivalent Se(5) atoms. The Cs(4)-Se(1) bond length is 4.32 Å. The Cs(4)-Se(2) bond length is 3.86 Å. The Cs(4)-Se(4) bond length is 4.19 Å. The Cs(4)-Se(7) bond length is 4.24 Å. The Cs(4)-Se(8) bond length is 3.99 Å. The Cs(4)-Se(9) bond length is 3.87 Å. There is one shorter (3.95 Å) and one longer (4.03 Å) Cs(4)-Se(5) bond length. There are nine inequivalent B sites. In the first B site, B(1) is bonded in a distorted single-bond geometry to one B(2), one B(3), one B(4), one B(5), one B(6), and one Se(1) atom. The B(1)-B(2) bond length is 1.77 Å. The B(1)-B(3) bond length is 1.77 Å. The B(1)-B(4) bond length is 1.78 Å. The B(1)-B(5) bond length is 1.78 Å. The B(1)-B(6) bond length is 1.77 Å. The B(1)-Se(1) bond length is 2.02 Å. In the second B site, B(2) is bonded in a 6-coordinate geometry to one B(1), one B(3), one B(4), one B(5), one B(6), and one Se(2) atom. The B(2)-B(3) bond length is 1.78 Å. The B(2)-B(4) bond length is 1.80 Å. The B(2)-B(5) bond length is 1.80 Å. The B(2)-B(6) bond length is 1.78 Å. The B(2)-Se(2) bond length is 2.02 Å. In the third B site, B(3) is bonded in a distorted single-bond geometry to one B(1), one B(2), one B(4), one B(5), one B(6), and one Se(3) atom. The B(3)-B(4) bond length is 1.78 Å. The B(3)-B(5) bond length is 1.78 Å. The B(3)-B(6) bond length is 1.77 Å. The B(3)-Se(3) bond length is 2.01 Å. In the fourth B site, B(4) is bonded in a 6-coordinate geometry to one B(1), one B(2), one B(3), one B(5), one B(6), and one Se(4) atom. The B(4)-B(5) bond length is 1.79 Å. The B(4)-B(6) bond length is 1.78 Å. The B(4)-Se(4) bond length is 2.01 Å. In the fifth B site, B(5) is bonded in a 6-coordinate geometry to one B(1), one B(2), one B(3), one B(4), one B(6), and one Se(5) atom. The B(5)-B(6) bond length is 1.78 Å. The B(5)-Se(5) bond length is 2.02 Å. In the sixth B site, B(6) is bonded in a distorted single-bond geometry to one B(1), one B(2), one B(3), one B(4), one B(5), and one Se(6) atom. The B(6)-Se(6) bond length is 2.01 Å. In the seventh B site, B(7) is bonded in a trigonal planar geometry to one Cs(2), one Se(1), one Se(2), and one Se(7) atom. The B(7)-Se(1) bond length is 1.98 Å. The B(7)-Se(2) bond length is 2.00 Å. The B(7)-Se(7) bond length is 1.92 Å. In the eighth B site, B(8) is bonded in a trigonal planar geometry to one Cs(1), one Cs(2), one Se(3), one Se(4), and one Se(8) atom. The B(8)-Se(3) bond length is 1.98 Å. The B(8)-Se(4) bond length is 1.99 Å. The B(8)-Se(8) bond length is 1.92 Å. In the ninth B site, B(9) is bonded in a trigonal planar geometry to one Cs(1), one Se(5), one Se(6), and one Se(9) atom. The B(9)-Se(5) bond length is 2.00 Å. The B(9)-Se(6) bond length is 1.98 Å. The B(9)-Se(9) bond length is 1.92 Å. There are nine inequivalent Se sites. In the first Se site, Se(1) is bonded in a distorted water-like geometry to one Cs(2), one Cs(3), one Cs(4), one B(1), and one B(7) atom. In the second Se site, Se(2) is bonded in a distorted water-like geometry to one Cs(4), two equivalent Cs(1), one B(2), and one B(7) atom. In the third Se site, Se(3) is bonded in a distorted L-shaped geometry to one Cs(1), one Cs(2), one B(3), and one B(8) atom. In the fourth Se site, Se(4) is bonded in a distorted water-like geometry to one Cs(2), one Cs(3), one Cs(4), one B(4), and one B(8) atom. In the fifth Se site, Se(5) is bonded in a distorted water-like geometry to one Cs(2), two equivalent Cs(4), one B(5), and one B(9) atom. In the sixth Se site, Se(6) is bonded in a distorted water-like geometry to one Cs(1), one Cs(3), one B(6), and one B(9) atom. In the seventh Se site, Se(7) is bonded in a distorted single-bond geometry to one Cs(2), one Cs(4), two equivalent Cs(1), two equivalent Cs(3), and one B(7) atom. In the eighth Se site, Se(8) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(3), one Cs(4), two equivalent Cs(2), and one B(8) atom. In the ninth Se site, Se(9) is bonded in a distorted single-bond geometry to one Cs(1), one Cs(2), one Cs(4), two equivalent Cs(3), and one B(9) atom.