CsBi2Br7 crystallizes in the triclinic P-1 space group. Cs(1) is bonded to one Br(2), one Br(5), one Br(7), two equivalent Br(3), two equivalent Br(4), two equivalent Br(6), and three equivalent Br(1) atoms to form CsBr12 cuboctahedra that share corners with two equivalent Cs(1)Br12 cuboctahedra,  a cornercorner with one Bi(1)Br6 octahedra, corners with three equivalent Bi(2)Br6 octahedra, edges with three equivalent Cs(1)Br12 cuboctahedra,  an edgeedge with one Bi(2)Br6 octahedra, edges with two equivalent Bi(1)Br6 octahedra,  a faceface with one Cs(1)Br12 cuboctahedra,  a faceface with one Bi(2)Br6 octahedra, and faces with two equivalent Bi(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 42-46°. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one Br(1), one Br(2), one Br(3), one Br(5), and two equivalent Br(4) atoms to form BiBr6 octahedra that share  a cornercorner with one Cs(1)Br12 cuboctahedra, corners with three equivalent Bi(2)Br6 octahedra, edges with two equivalent Cs(1)Br12 cuboctahedra,  an edgeedge with one Bi(1)Br6 octahedra, and faces with two equivalent Cs(1)Br12 cuboctahedra. The corner-sharing octahedral tilt angles range from 53-57°. In the second Bi site, Bi(2) is bonded to one Br(2), one Br(3), one Br(5), one Br(6), and two equivalent Br(7) atoms to form BiBr6 octahedra that share corners with three equivalent Cs(1)Br12 cuboctahedra, corners with three equivalent Bi(1)Br6 octahedra,  an edgeedge with one Cs(1)Br12 cuboctahedra,  an edgeedge with one Bi(2)Br6 octahedra, and  a faceface with one Cs(1)Br12 cuboctahedra. The corner-sharing octahedral tilt angles range from 53-57°. There are seven inequivalent Br sites. In the first Br site, Br(1) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Bi(1) atom. In the second Br site, Br(2) is bonded in a 3-coordinate geometry to one Cs(1), one Bi(1), and one Bi(2) atom. In the third Br site, Br(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Cs(1), one Bi(1), and one Bi(2) atom. In the fourth Br site, Br(4) is bonded in a 4-coordinate geometry to two equivalent Cs(1) and two equivalent Bi(1) atoms. In the fifth Br site, Br(5) is bonded in a 3-coordinate geometry to one Cs(1), one Bi(1), and one Bi(2) atom. In the sixth Br site, Br(6) is bonded in a distorted single-bond geometry to two equivalent Cs(1) and one Bi(2) atom. In the seventh Br site, Br(7) is bonded in a distorted T-shaped geometry to one Cs(1) and two equivalent Bi(2) atoms.
CsBi2Br7 crystallizes in the triclinic P-1 space group. Cs(1) is bonded to one Br(2), one Br(5), one Br(7), two equivalent Br(3), two equivalent Br(4), two equivalent Br(6), and three equivalent Br(1) atoms to form CsBr12 cuboctahedra that share corners with two equivalent Cs(1)Br12 cuboctahedra,  a cornercorner with one Bi(1)Br6 octahedra, corners with three equivalent Bi(2)Br6 octahedra, edges with three equivalent Cs(1)Br12 cuboctahedra,  an edgeedge with one Bi(2)Br6 octahedra, edges with two equivalent Bi(1)Br6 octahedra,  a faceface with one Cs(1)Br12 cuboctahedra,  a faceface with one Bi(2)Br6 octahedra, and faces with two equivalent Bi(1)Br6 octahedra. The corner-sharing octahedral tilt angles range from 42-46°. The Cs(1)-Br(2) bond length is 3.83 Å. The Cs(1)-Br(5) bond length is 3.93 Å. The Cs(1)-Br(7) bond length is 3.94 Å. There is one shorter (3.93 Å) and one longer (3.98 Å) Cs(1)-Br(3) bond length. There is one shorter (4.03 Å) and one longer (4.18 Å) Cs(1)-Br(4) bond length. There is one shorter (3.90 Å) and one longer (3.91 Å) Cs(1)-Br(6) bond length. There are two shorter (4.05 Å) and one longer (4.20 Å) Cs(1)-Br(1) bond length. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one Br(1), one Br(2), one Br(3), one Br(5), and two equivalent Br(4) atoms to form BiBr6 octahedra that share  a cornercorner with one Cs(1)Br12 cuboctahedra, corners with three equivalent Bi(2)Br6 octahedra, edges with two equivalent Cs(1)Br12 cuboctahedra,  an edgeedge with one Bi(1)Br6 octahedra, and faces with two equivalent Cs(1)Br12 cuboctahedra. The corner-sharing octahedral tilt angles range from 53-57°. The Bi(1)-Br(1) bond length is 2.69 Å. The Bi(1)-Br(2) bond length is 2.82 Å. The Bi(1)-Br(3) bond length is 2.86 Å. The Bi(1)-Br(5) bond length is 3.12 Å. There is one shorter (2.92 Å) and one longer (2.96 Å) Bi(1)-Br(4) bond length. In the second Bi site, Bi(2) is bonded to one Br(2), one Br(3), one Br(5), one Br(6), and two equivalent Br(7) atoms to form BiBr6 octahedra that share corners with three equivalent Cs(1)Br12 cuboctahedra, corners with three equivalent Bi(1)Br6 octahedra,  an edgeedge with one Cs(1)Br12 cuboctahedra,  an edgeedge with one Bi(2)Br6 octahedra, and  a faceface with one Cs(1)Br12 cuboctahedra. The corner-sharing octahedral tilt angles range from 53-57°. The Bi(2)-Br(2) bond length is 3.01 Å. The Bi(2)-Br(3) bond length is 3.03 Å. The Bi(2)-Br(5) bond length is 2.78 Å. The Bi(2)-Br(6) bond length is 2.68 Å. There is one shorter (2.78 Å) and one longer (3.12 Å) Bi(2)-Br(7) bond length. There are seven inequivalent Br sites. In the first Br site, Br(1) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Bi(1) atom. In the second Br site, Br(2) is bonded in a 3-coordinate geometry to one Cs(1), one Bi(1), and one Bi(2) atom. In the third Br site, Br(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Cs(1), one Bi(1), and one Bi(2) atom. In the fourth Br site, Br(4) is bonded in a 4-coordinate geometry to two equivalent Cs(1) and two equivalent Bi(1) atoms. In the fifth Br site, Br(5) is bonded in a 3-coordinate geometry to one Cs(1), one Bi(1), and one Bi(2) atom. In the sixth Br site, Br(6) is bonded in a distorted single-bond geometry to two equivalent Cs(1) and one Bi(2) atom. In the seventh Br site, Br(7) is bonded in a distorted T-shaped geometry to one Cs(1) and two equivalent Bi(2) atoms.