TlBi(PSe3)2 crystallizes in the monoclinic P2_1/c space group. Tl(1) is bonded in a 7-coordinate geometry to one Se(5), one Se(6), two equivalent Se(1), and three equivalent Se(3) atoms. Bi(1) is bonded to one Se(1), one Se(4), one Se(5), one Se(6), and two equivalent Se(2) atoms to form distorted BiSe6 pentagonal pyramids that share corners with two equivalent Bi(1)Se6 pentagonal pyramids,  a cornercorner with one P(1)PSe3 tetrahedra, corners with three equivalent P(2)PSe3 tetrahedra, and  an edgeedge with one P(1)PSe3 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one P(2), one Se(1), one Se(4), and one Se(5) atom to form distorted PPSe3 tetrahedra that share  a cornercorner with one Bi(1)Se6 pentagonal pyramid and  an edgeedge with one Bi(1)Se6 pentagonal pyramid. In the second P site, P(2) is bonded to one P(1), one Se(2), one Se(3), and one Se(6) atom to form distorted PPSe3 tetrahedra that share corners with three equivalent Bi(1)Se6 pentagonal pyramids. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 2-coordinate geometry to two equivalent Tl(1), one Bi(1), and one P(1) atom. In the second Se site, Se(2) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Bi(1) and one P(2) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to three equivalent Tl(1) and one P(2) atom. In the fourth Se site, Se(4) is bonded in a distorted L-shaped geometry to one Bi(1) and one P(1) atom. In the fifth Se site, Se(5) is bonded in a 2-coordinate geometry to one Tl(1), one Bi(1), and one P(1) atom. In the sixth Se site, Se(6) is bonded in a 3-coordinate geometry to one Tl(1), one Bi(1), and one P(2) atom.
TlBi(PSe3)2 crystallizes in the monoclinic P2_1/c space group. Tl(1) is bonded in a 7-coordinate geometry to one Se(5), one Se(6), two equivalent Se(1), and three equivalent Se(3) atoms. The Tl(1)-Se(5) bond length is 3.44 Å. The Tl(1)-Se(6) bond length is 3.28 Å. There is one shorter (3.39 Å) and one longer (3.40 Å) Tl(1)-Se(1) bond length. There are a spread of Tl(1)-Se(3) bond distances ranging from 3.30-3.46 Å. Bi(1) is bonded to one Se(1), one Se(4), one Se(5), one Se(6), and two equivalent Se(2) atoms to form distorted BiSe6 pentagonal pyramids that share corners with two equivalent Bi(1)Se6 pentagonal pyramids,  a cornercorner with one P(1)PSe3 tetrahedra, corners with three equivalent P(2)PSe3 tetrahedra, and  an edgeedge with one P(1)PSe3 tetrahedra. The Bi(1)-Se(1) bond length is 2.88 Å. The Bi(1)-Se(4) bond length is 2.87 Å. The Bi(1)-Se(5) bond length is 3.14 Å. The Bi(1)-Se(6) bond length is 2.92 Å. There is one shorter (3.08 Å) and one longer (3.11 Å) Bi(1)-Se(2) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded to one P(2), one Se(1), one Se(4), and one Se(5) atom to form distorted PPSe3 tetrahedra that share  a cornercorner with one Bi(1)Se6 pentagonal pyramid and  an edgeedge with one Bi(1)Se6 pentagonal pyramid. The P(1)-P(2) bond length is 2.24 Å. The P(1)-Se(1) bond length is 2.20 Å. The P(1)-Se(4) bond length is 2.21 Å. The P(1)-Se(5) bond length is 2.16 Å. In the second P site, P(2) is bonded to one P(1), one Se(2), one Se(3), and one Se(6) atom to form distorted PPSe3 tetrahedra that share corners with three equivalent Bi(1)Se6 pentagonal pyramids. The P(2)-Se(2) bond length is 2.20 Å. The P(2)-Se(3) bond length is 2.15 Å. The P(2)-Se(6) bond length is 2.22 Å. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 2-coordinate geometry to two equivalent Tl(1), one Bi(1), and one P(1) atom. In the second Se site, Se(2) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Bi(1) and one P(2) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to three equivalent Tl(1) and one P(2) atom. In the fourth Se site, Se(4) is bonded in a distorted L-shaped geometry to one Bi(1) and one P(1) atom. In the fifth Se site, Se(5) is bonded in a 2-coordinate geometry to one Tl(1), one Bi(1), and one P(1) atom. In the sixth Se site, Se(6) is bonded in a 3-coordinate geometry to one Tl(1), one Bi(1), and one P(2) atom.