Cs3Y7Se12 crystallizes in the orthorhombic Pmn2_1 space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(11), two equivalent Se(7), and two equivalent Se(9) atoms. In the second Cs site, Cs(2) is bonded in a 7-coordinate geometry to one Se(1), two equivalent Se(10), two equivalent Se(12), and two equivalent Se(8) atoms. In the third Cs site, Cs(3) is bonded in a 6-coordinate geometry to one Se(10), one Se(12), two equivalent Se(5), and two equivalent Se(6) atoms. There are seven inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(11), one Se(3), two equivalent Se(1), and two equivalent Se(5) atoms to form edge-sharing YSe6 octahedra. In the second Y site, Y(2) is bonded to one Se(12), one Se(4), two equivalent Se(2), and two equivalent Se(6) atoms to form edge-sharing YSe6 octahedra. In the third Y site, Y(3) is bonded to one Se(1), one Se(9), two equivalent Se(3), and two equivalent Se(8) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. In the fourth Y site, Y(4) is bonded to one Se(10), one Se(2), two equivalent Se(4), and two equivalent Se(7) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-11°. In the fifth Y site, Y(5) is bonded to one Se(1), one Se(2), two equivalent Se(11), and two equivalent Se(12) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 11-12°. In the sixth Y site, Y(6) is bonded to one Se(5), one Se(7), two equivalent Se(10), and two equivalent Se(3) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the seventh Y site, Y(7) is bonded to one Se(6), one Se(8), two equivalent Se(4), and two equivalent Se(9) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cs(2), one Y(3), one Y(5), and two equivalent Y(1) atoms to form distorted SeCsY4 trigonal bipyramids that share  a cornercorner with one Se(9)Cs2Y3 trigonal bipyramid,  a cornercorner with one Se(2)CsY4 trigonal bipyramid, corners with two equivalent Se(5)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(1)CsY4 trigonal bipyramids, edges with two equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(5)Cs2Y3 trigonal bipyramid, and edges with two equivalent Se(8)Cs2Y3 trigonal bipyramids. In the second Se site, Se(2) is bonded to one Cs(1), one Y(4), one Y(5), and two equivalent Y(2) atoms to form distorted SeCsY4 trigonal bipyramids that share  a cornercorner with one Se(1)CsY4 trigonal bipyramid, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(2)CsY4 trigonal bipyramids, edges with two equivalent Se(4)Y5 square pyramids, and edges with two equivalent Se(7)Cs2Y3 trigonal bipyramids. In the third Se site, Se(3) is bonded to one Y(1), two equivalent Y(3), and two equivalent Y(6) atoms to form SeY5 square pyramids that share corners with two equivalent Se(7)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(8)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids, edges with two equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(8)Cs2Y3 trigonal bipyramid, edges with two equivalent Se(5)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(1)CsY4 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to one Y(2), two equivalent Y(4), and two equivalent Y(7) atoms to form SeY5 square pyramids that share corners with two equivalent Se(7)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(8)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids, edges with two equivalent Se(4)Y5 square pyramids,  an edgeedge with one Se(7)Cs2Y3 trigonal bipyramid,  an edgeedge with one Se(9)Cs2Y3 trigonal bipyramid, and edges with two equivalent Se(2)CsY4 trigonal bipyramids. In the fifth Se site, Se(5) is bonded to two equivalent Cs(3), one Y(6), and two equivalent Y(1) atoms to form distorted SeCs2Y3 trigonal bipyramids that share  a cornercorner with one Se(7)Cs2Y3 trigonal bipyramid, corners with two equivalent Se(1)CsY4 trigonal bipyramids, edges with two equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(1)CsY4 trigonal bipyramid, and edges with two equivalent Se(5)Cs2Y3 trigonal bipyramids. In the sixth Se site, Se(6) is bonded in a 5-coordinate geometry to two equivalent Cs(3), one Y(7), and two equivalent Y(2) atoms. In the seventh Se site, Se(7) is bonded to two equivalent Cs(1), one Y(6), and two equivalent Y(4) atoms to form distorted SeCs2Y3 trigonal bipyramids that share corners with two equivalent Se(3)Y5 square pyramids, corners with two equivalent Se(4)Y5 square pyramids,  a cornercorner with one Se(5)Cs2Y3 trigonal bipyramid, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids,  an edgeedge with one Se(4)Y5 square pyramid,  an edgeedge with one Se(9)Cs2Y3 trigonal bipyramid, edges with two equivalent Se(7)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(2)CsY4 trigonal bipyramids. In the eighth Se site, Se(8) is bonded to two equivalent Cs(2), one Y(7), and two equivalent Y(3) atoms to form distorted SeCs2Y3 trigonal bipyramids that share corners with two equivalent Se(3)Y5 square pyramids, corners with two equivalent Se(4)Y5 square pyramids,  an edgeedge with one Se(3)Y5 square pyramid, edges with two equivalent Se(8)Cs2Y3 trigonal bipyramids, edges with two equivalent Se(9)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(1)CsY4 trigonal bipyramids. In the ninth Se site, Se(9) is bonded to two equivalent Cs(1), one Y(3), and two equivalent Y(7) atoms to form distorted SeCs2Y3 trigonal bipyramids that share corners with two equivalent Se(3)Y5 square pyramids, corners with two equivalent Se(4)Y5 square pyramids,  a cornercorner with one Se(1)CsY4 trigonal bipyramid, corners with two equivalent Se(7)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(2)CsY4 trigonal bipyramids,  an edgeedge with one Se(4)Y5 square pyramid,  an edgeedge with one Se(7)Cs2Y3 trigonal bipyramid, edges with two equivalent Se(8)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(9)Cs2Y3 trigonal bipyramids. In the tenth Se site, Se(10) is bonded in a 6-coordinate geometry to one Cs(3), two equivalent Cs(2), one Y(4), and two equivalent Y(6) atoms. In the eleventh Se site, Se(11) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Y(1), and two equivalent Y(5) atoms. In the twelfth Se site, Se(12) is bonded in a 6-coordinate geometry to one Cs(3), two equivalent Cs(2), one Y(2), and two equivalent Y(5) atoms.
Cs3Y7Se12 crystallizes in the orthorhombic Pmn2_1 space group. There are three inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Se(2), two equivalent Se(11), two equivalent Se(7), and two equivalent Se(9) atoms. The Cs(1)-Se(2) bond length is 3.78 Å. Both Cs(1)-Se(11) bond lengths are 3.74 Å. Both Cs(1)-Se(7) bond lengths are 3.68 Å. Both Cs(1)-Se(9) bond lengths are 3.70 Å. In the second Cs site, Cs(2) is bonded in a 7-coordinate geometry to one Se(1), two equivalent Se(10), two equivalent Se(12), and two equivalent Se(8) atoms. The Cs(2)-Se(1) bond length is 3.71 Å. Both Cs(2)-Se(10) bond lengths are 3.70 Å. Both Cs(2)-Se(12) bond lengths are 3.82 Å. Both Cs(2)-Se(8) bond lengths are 3.54 Å. In the third Cs site, Cs(3) is bonded in a 6-coordinate geometry to one Se(10), one Se(12), two equivalent Se(5), and two equivalent Se(6) atoms. The Cs(3)-Se(10) bond length is 4.09 Å. The Cs(3)-Se(12) bond length is 3.75 Å. Both Cs(3)-Se(5) bond lengths are 3.52 Å. Both Cs(3)-Se(6) bond lengths are 3.63 Å. There are seven inequivalent Y sites. In the first Y site, Y(1) is bonded to one Se(11), one Se(3), two equivalent Se(1), and two equivalent Se(5) atoms to form edge-sharing YSe6 octahedra. The Y(1)-Se(11) bond length is 2.79 Å. The Y(1)-Se(3) bond length is 3.01 Å. Both Y(1)-Se(1) bond lengths are 2.87 Å. Both Y(1)-Se(5) bond lengths are 2.86 Å. In the second Y site, Y(2) is bonded to one Se(12), one Se(4), two equivalent Se(2), and two equivalent Se(6) atoms to form edge-sharing YSe6 octahedra. The Y(2)-Se(12) bond length is 2.83 Å. The Y(2)-Se(4) bond length is 2.98 Å. Both Y(2)-Se(2) bond lengths are 2.87 Å. Both Y(2)-Se(6) bond lengths are 2.86 Å. In the third Y site, Y(3) is bonded to one Se(1), one Se(9), two equivalent Se(3), and two equivalent Se(8) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. The Y(3)-Se(1) bond length is 2.87 Å. The Y(3)-Se(9) bond length is 2.85 Å. Both Y(3)-Se(3) bond lengths are 2.97 Å. Both Y(3)-Se(8) bond lengths are 2.80 Å. In the fourth Y site, Y(4) is bonded to one Se(10), one Se(2), two equivalent Se(4), and two equivalent Se(7) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 1-11°. The Y(4)-Se(10) bond length is 2.90 Å. The Y(4)-Se(2) bond length is 2.86 Å. Both Y(4)-Se(4) bond lengths are 2.98 Å. Both Y(4)-Se(7) bond lengths are 2.80 Å. In the fifth Y site, Y(5) is bonded to one Se(1), one Se(2), two equivalent Se(11), and two equivalent Se(12) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles range from 11-12°. The Y(5)-Se(1) bond length is 2.85 Å. The Y(5)-Se(2) bond length is 2.86 Å. Both Y(5)-Se(11) bond lengths are 2.87 Å. Both Y(5)-Se(12) bond lengths are 2.90 Å. In the sixth Y site, Y(6) is bonded to one Se(5), one Se(7), two equivalent Se(10), and two equivalent Se(3) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. The Y(6)-Se(5) bond length is 2.83 Å. The Y(6)-Se(7) bond length is 2.80 Å. Both Y(6)-Se(10) bond lengths are 2.84 Å. Both Y(6)-Se(3) bond lengths are 2.99 Å. In the seventh Y site, Y(7) is bonded to one Se(6), one Se(8), two equivalent Se(4), and two equivalent Se(9) atoms to form a mixture of edge and corner-sharing YSe6 octahedra. The corner-sharing octahedral tilt angles are 1°. The Y(7)-Se(6) bond length is 2.82 Å. The Y(7)-Se(8) bond length is 2.80 Å. Both Y(7)-Se(4) bond lengths are 3.03 Å. Both Y(7)-Se(9) bond lengths are 2.82 Å. There are twelve inequivalent Se sites. In the first Se site, Se(1) is bonded to one Cs(2), one Y(3), one Y(5), and two equivalent Y(1) atoms to form distorted SeCsY4 trigonal bipyramids that share  a cornercorner with one Se(9)Cs2Y3 trigonal bipyramid,  a cornercorner with one Se(2)CsY4 trigonal bipyramid, corners with two equivalent Se(5)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(1)CsY4 trigonal bipyramids, edges with two equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(5)Cs2Y3 trigonal bipyramid, and edges with two equivalent Se(8)Cs2Y3 trigonal bipyramids. In the second Se site, Se(2) is bonded to one Cs(1), one Y(4), one Y(5), and two equivalent Y(2) atoms to form distorted SeCsY4 trigonal bipyramids that share  a cornercorner with one Se(1)CsY4 trigonal bipyramid, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(2)CsY4 trigonal bipyramids, edges with two equivalent Se(4)Y5 square pyramids, and edges with two equivalent Se(7)Cs2Y3 trigonal bipyramids. In the third Se site, Se(3) is bonded to one Y(1), two equivalent Y(3), and two equivalent Y(6) atoms to form SeY5 square pyramids that share corners with two equivalent Se(7)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(8)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids, edges with two equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(8)Cs2Y3 trigonal bipyramid, edges with two equivalent Se(5)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(1)CsY4 trigonal bipyramids. In the fourth Se site, Se(4) is bonded to one Y(2), two equivalent Y(4), and two equivalent Y(7) atoms to form SeY5 square pyramids that share corners with two equivalent Se(7)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(8)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids, edges with two equivalent Se(4)Y5 square pyramids,  an edgeedge with one Se(7)Cs2Y3 trigonal bipyramid,  an edgeedge with one Se(9)Cs2Y3 trigonal bipyramid, and edges with two equivalent Se(2)CsY4 trigonal bipyramids. In the fifth Se site, Se(5) is bonded to two equivalent Cs(3), one Y(6), and two equivalent Y(1) atoms to form distorted SeCs2Y3 trigonal bipyramids that share  a cornercorner with one Se(7)Cs2Y3 trigonal bipyramid, corners with two equivalent Se(1)CsY4 trigonal bipyramids, edges with two equivalent Se(3)Y5 square pyramids,  an edgeedge with one Se(1)CsY4 trigonal bipyramid, and edges with two equivalent Se(5)Cs2Y3 trigonal bipyramids. In the sixth Se site, Se(6) is bonded in a 5-coordinate geometry to two equivalent Cs(3), one Y(7), and two equivalent Y(2) atoms. In the seventh Se site, Se(7) is bonded to two equivalent Cs(1), one Y(6), and two equivalent Y(4) atoms to form distorted SeCs2Y3 trigonal bipyramids that share corners with two equivalent Se(3)Y5 square pyramids, corners with two equivalent Se(4)Y5 square pyramids,  a cornercorner with one Se(5)Cs2Y3 trigonal bipyramid, corners with two equivalent Se(9)Cs2Y3 trigonal bipyramids,  an edgeedge with one Se(4)Y5 square pyramid,  an edgeedge with one Se(9)Cs2Y3 trigonal bipyramid, edges with two equivalent Se(7)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(2)CsY4 trigonal bipyramids. In the eighth Se site, Se(8) is bonded to two equivalent Cs(2), one Y(7), and two equivalent Y(3) atoms to form distorted SeCs2Y3 trigonal bipyramids that share corners with two equivalent Se(3)Y5 square pyramids, corners with two equivalent Se(4)Y5 square pyramids,  an edgeedge with one Se(3)Y5 square pyramid, edges with two equivalent Se(8)Cs2Y3 trigonal bipyramids, edges with two equivalent Se(9)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(1)CsY4 trigonal bipyramids. In the ninth Se site, Se(9) is bonded to two equivalent Cs(1), one Y(3), and two equivalent Y(7) atoms to form distorted SeCs2Y3 trigonal bipyramids that share corners with two equivalent Se(3)Y5 square pyramids, corners with two equivalent Se(4)Y5 square pyramids,  a cornercorner with one Se(1)CsY4 trigonal bipyramid, corners with two equivalent Se(7)Cs2Y3 trigonal bipyramids, corners with two equivalent Se(2)CsY4 trigonal bipyramids,  an edgeedge with one Se(4)Y5 square pyramid,  an edgeedge with one Se(7)Cs2Y3 trigonal bipyramid, edges with two equivalent Se(8)Cs2Y3 trigonal bipyramids, and edges with two equivalent Se(9)Cs2Y3 trigonal bipyramids. In the tenth Se site, Se(10) is bonded in a 6-coordinate geometry to one Cs(3), two equivalent Cs(2), one Y(4), and two equivalent Y(6) atoms. In the eleventh Se site, Se(11) is bonded in a 5-coordinate geometry to two equivalent Cs(1), one Y(1), and two equivalent Y(5) atoms. In the twelfth Se site, Se(12) is bonded in a 6-coordinate geometry to one Cs(3), two equivalent Cs(2), one Y(2), and two equivalent Y(5) atoms.