RbBi4Se7 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a 6-coordinate geometry to one Se(3), one Se(5), two equivalent Se(2), and two equivalent Se(4) atoms. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one Se(1), one Se(3), two equivalent Se(6), and two equivalent Se(7) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 2-5°. In the second Bi site, Bi(2) is bonded to one Se(1), two equivalent Se(5), and three equivalent Se(2) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the third Bi site, Bi(3) is bonded to one Se(4), two equivalent Se(3), and three equivalent Se(6) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. In the fourth Bi site, Bi(4) is bonded to one Se(5), one Se(6), two equivalent Se(1), and two equivalent Se(4) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 6°. There are seven inequivalent Se sites. In the first Se site, Se(7) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Bi(1) and one Se(7) atom. In the second Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Bi(1), one Bi(2), and two equivalent Bi(4) atoms. In the third Se site, Se(2) is bonded to two equivalent Rb(1) and three equivalent Bi(2) atoms to form a mixture of corner and edge-sharing SeRb2Bi3 square pyramids. In the fourth Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Rb(1), one Bi(1), and two equivalent Bi(3) atoms. In the fifth Se site, Se(4) is bonded to two equivalent Rb(1), one Bi(3), and two equivalent Bi(4) atoms to form SeRb2Bi3 square pyramids that share  a cornercorner with one Se(6)Bi6 octahedra, corners with two equivalent Se(2)Rb2Bi3 square pyramids, edges with two equivalent Se(6)Bi6 octahedra,  an edgeedge with one Se(2)Rb2Bi3 square pyramid, and edges with two equivalent Se(4)Rb2Bi3 square pyramids. The corner-sharing octahedral tilt angles are 10°. In the sixth Se site, Se(5) is bonded in a rectangular see-saw-like geometry to one Rb(1), one Bi(4), and two equivalent Bi(2) atoms. In the seventh Se site, Se(6) is bonded to one Bi(4), two equivalent Bi(1), and three equivalent Bi(3) atoms to form SeBi6 octahedra that share  a cornercorner with one Se(4)Rb2Bi3 square pyramid, edges with four equivalent Se(6)Bi6 octahedra, and edges with two equivalent Se(4)Rb2Bi3 square pyramids.
RbBi4Se7 crystallizes in the monoclinic C2/m space group. Rb(1) is bonded in a 6-coordinate geometry to one Se(3), one Se(5), two equivalent Se(2), and two equivalent Se(4) atoms. The Rb(1)-Se(3) bond length is 3.80 Å. The Rb(1)-Se(5) bond length is 3.50 Å. Both Rb(1)-Se(2) bond lengths are 3.43 Å. Both Rb(1)-Se(4) bond lengths are 3.49 Å. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one Se(1), one Se(3), two equivalent Se(6), and two equivalent Se(7) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 2-5°. The Bi(1)-Se(1) bond length is 2.87 Å. The Bi(1)-Se(3) bond length is 3.06 Å. Both Bi(1)-Se(6) bond lengths are 3.01 Å. Both Bi(1)-Se(7) bond lengths are 2.99 Å. In the second Bi site, Bi(2) is bonded to one Se(1), two equivalent Se(5), and three equivalent Se(2) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 2°. The Bi(2)-Se(1) bond length is 3.18 Å. Both Bi(2)-Se(5) bond lengths are 2.95 Å. There is one shorter (2.77 Å) and two longer (3.02 Å) Bi(2)-Se(2) bond lengths. In the third Bi site, Bi(3) is bonded to one Se(4), two equivalent Se(3), and three equivalent Se(6) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles range from 5-6°. The Bi(3)-Se(4) bond length is 2.81 Å. Both Bi(3)-Se(3) bond lengths are 2.85 Å. All Bi(3)-Se(6) bond lengths are 3.16 Å. In the fourth Bi site, Bi(4) is bonded to one Se(5), one Se(6), two equivalent Se(1), and two equivalent Se(4) atoms to form a mixture of corner and edge-sharing BiSe6 octahedra. The corner-sharing octahedral tilt angles are 6°. The Bi(4)-Se(5) bond length is 2.85 Å. The Bi(4)-Se(6) bond length is 3.15 Å. Both Bi(4)-Se(1) bond lengths are 2.96 Å. Both Bi(4)-Se(4) bond lengths are 3.01 Å. There are seven inequivalent Se sites. In the first Se site, Se(7) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Bi(1) and one Se(7) atom. The Se(7)-Se(7) bond length is 2.39 Å. In the second Se site, Se(1) is bonded in a rectangular see-saw-like geometry to one Bi(1), one Bi(2), and two equivalent Bi(4) atoms. In the third Se site, Se(2) is bonded to two equivalent Rb(1) and three equivalent Bi(2) atoms to form a mixture of corner and edge-sharing SeRb2Bi3 square pyramids. In the fourth Se site, Se(3) is bonded in a rectangular see-saw-like geometry to one Rb(1), one Bi(1), and two equivalent Bi(3) atoms. In the fifth Se site, Se(4) is bonded to two equivalent Rb(1), one Bi(3), and two equivalent Bi(4) atoms to form SeRb2Bi3 square pyramids that share  a cornercorner with one Se(6)Bi6 octahedra, corners with two equivalent Se(2)Rb2Bi3 square pyramids, edges with two equivalent Se(6)Bi6 octahedra,  an edgeedge with one Se(2)Rb2Bi3 square pyramid, and edges with two equivalent Se(4)Rb2Bi3 square pyramids. The corner-sharing octahedral tilt angles are 10°. In the sixth Se site, Se(5) is bonded in a rectangular see-saw-like geometry to one Rb(1), one Bi(4), and two equivalent Bi(2) atoms. In the seventh Se site, Se(6) is bonded to one Bi(4), two equivalent Bi(1), and three equivalent Bi(3) atoms to form SeBi6 octahedra that share  a cornercorner with one Se(4)Rb2Bi3 square pyramid, edges with four equivalent Se(6)Bi6 octahedra, and edges with two equivalent Se(4)Rb2Bi3 square pyramids.