Cs2TlCl5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to two equivalent Cl(1), two equivalent Cl(3), two equivalent Cl(4), and four equivalent Cl(2) atoms. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent Cl(1), two equivalent Cl(3), two equivalent Cl(4), and four equivalent Cl(2) atoms. Tl(1) is bonded to one Cl(3), one Cl(4), two equivalent Cl(1), and two equivalent Cl(2) atoms to form corner-sharing TlCl6 octahedra. The corner-sharing octahedra are not tilted. There are four inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Tl(1) atoms to form distorted ClCs4Tl2 octahedra that share corners with four equivalent Cl(3)Cs4Tl square pyramids, corners with four equivalent Cl(4)Cs4Tl trigonal bipyramids, faces with two equivalent Cl(1)Cs4Tl2 octahedra, faces with two equivalent Cl(3)Cs4Tl square pyramids, and faces with two equivalent Cl(4)Cs4Tl trigonal bipyramids. In the second Cl site, Cl(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1), two equivalent Cs(2), and one Tl(1) atom. In the third Cl site, Cl(3) is bonded to two equivalent Cs(1), two equivalent Cs(2), and one Tl(1) atom to form distorted ClCs4Tl square pyramids that share corners with four equivalent Cl(1)Cs4Tl2 octahedra, corners with four equivalent Cl(3)Cs4Tl square pyramids,  a cornercorner with one Cl(4)Cs4Tl trigonal bipyramid, edges with four equivalent Cl(4)Cs4Tl trigonal bipyramids, and faces with two equivalent Cl(1)Cs4Tl2 octahedra. The corner-sharing octahedral tilt angles range from 37-63°. In the fourth Cl site, Cl(4) is bonded to two equivalent Cs(1), two equivalent Cs(2), and one Tl(1) atom to form distorted ClCs4Tl trigonal bipyramids that share corners with four equivalent Cl(1)Cs4Tl2 octahedra,  a cornercorner with one Cl(3)Cs4Tl square pyramid, corners with four equivalent Cl(4)Cs4Tl trigonal bipyramids, edges with four equivalent Cl(3)Cs4Tl square pyramids, and faces with two equivalent Cl(1)Cs4Tl2 octahedra. The corner-sharing octahedral tilt angles range from 53-59°.
Cs2TlCl5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 10-coordinate geometry to two equivalent Cl(1), two equivalent Cl(3), two equivalent Cl(4), and four equivalent Cl(2) atoms. Both Cs(1)-Cl(1) bond lengths are 3.60 Å. There is one shorter (3.57 Å) and one longer (3.58 Å) Cs(1)-Cl(3) bond length. Both Cs(1)-Cl(4) bond lengths are 3.77 Å. There are two shorter (3.65 Å) and two longer (3.66 Å) Cs(1)-Cl(2) bond lengths. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent Cl(1), two equivalent Cl(3), two equivalent Cl(4), and four equivalent Cl(2) atoms. Both Cs(2)-Cl(1) bond lengths are 3.78 Å. Both Cs(2)-Cl(3) bond lengths are 3.77 Å. There is one shorter (3.60 Å) and one longer (3.78 Å) Cs(2)-Cl(4) bond length. There are two shorter (3.56 Å) and two longer (3.75 Å) Cs(2)-Cl(2) bond lengths. Tl(1) is bonded to one Cl(3), one Cl(4), two equivalent Cl(1), and two equivalent Cl(2) atoms to form corner-sharing TlCl6 octahedra. The corner-sharing octahedra are not tilted. The Tl(1)-Cl(3) bond length is 2.55 Å. The Tl(1)-Cl(4) bond length is 2.51 Å. Both Tl(1)-Cl(1) bond lengths are 2.79 Å. Both Tl(1)-Cl(2) bond lengths are 2.56 Å. There are four inequivalent Cl sites. In the first Cl site, Cl(1) is bonded to two equivalent Cs(1), two equivalent Cs(2), and two equivalent Tl(1) atoms to form distorted ClCs4Tl2 octahedra that share corners with four equivalent Cl(3)Cs4Tl square pyramids, corners with four equivalent Cl(4)Cs4Tl trigonal bipyramids, faces with two equivalent Cl(1)Cs4Tl2 octahedra, faces with two equivalent Cl(3)Cs4Tl square pyramids, and faces with two equivalent Cl(4)Cs4Tl trigonal bipyramids. In the second Cl site, Cl(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1), two equivalent Cs(2), and one Tl(1) atom. In the third Cl site, Cl(3) is bonded to two equivalent Cs(1), two equivalent Cs(2), and one Tl(1) atom to form distorted ClCs4Tl square pyramids that share corners with four equivalent Cl(1)Cs4Tl2 octahedra, corners with four equivalent Cl(3)Cs4Tl square pyramids,  a cornercorner with one Cl(4)Cs4Tl trigonal bipyramid, edges with four equivalent Cl(4)Cs4Tl trigonal bipyramids, and faces with two equivalent Cl(1)Cs4Tl2 octahedra. The corner-sharing octahedral tilt angles range from 37-63°. In the fourth Cl site, Cl(4) is bonded to two equivalent Cs(1), two equivalent Cs(2), and one Tl(1) atom to form distorted ClCs4Tl trigonal bipyramids that share corners with four equivalent Cl(1)Cs4Tl2 octahedra,  a cornercorner with one Cl(3)Cs4Tl square pyramid, corners with four equivalent Cl(4)Cs4Tl trigonal bipyramids, edges with four equivalent Cl(3)Cs4Tl square pyramids, and faces with two equivalent Cl(1)Cs4Tl2 octahedra. The corner-sharing octahedral tilt angles range from 53-59°.