SmTl(PSe3)2 crystallizes in the monoclinic P2_1 space group. Sm(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms. Tl(1) is bonded in a 5-coordinate geometry to one Se(2), two equivalent Se(1), and two equivalent Se(3) atoms. There are two inequivalent P sites. In the first P site, P(1) is bonded in a distorted tetrahedral geometry to one P(2), one Se(1), one Se(3), and one Se(4) atom. In the second P site, P(2) is bonded in a distorted tetrahedral geometry to one P(1), one Se(2), one Se(5), and one Se(6) atom. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 2-coordinate geometry to one Sm(1), two equivalent Tl(1), and one P(1) atom. In the second Se site, Se(2) is bonded in a distorted L-shaped geometry to one Sm(1), one Tl(1), and one P(2) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to two equivalent Tl(1) and one P(1) atom. In the fourth Se site, Se(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Sm(1) and one P(1) atom. In the fifth Se site, Se(5) is bonded in a distorted T-shaped geometry to two equivalent Sm(1) and one P(2) atom. In the sixth Se site, Se(6) is bonded in a trigonal non-coplanar geometry to two equivalent Sm(1) and one P(2) atom.
SmTl(PSe3)2 crystallizes in the monoclinic P2_1 space group. Sm(1) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms. The Sm(1)-Se(1) bond length is 3.08 Å. The Sm(1)-Se(2) bond length is 3.11 Å. There is one shorter (3.07 Å) and one longer (3.19 Å) Sm(1)-Se(4) bond length. There is one shorter (3.07 Å) and one longer (3.09 Å) Sm(1)-Se(5) bond length. There is one shorter (3.06 Å) and one longer (3.16 Å) Sm(1)-Se(6) bond length. Tl(1) is bonded in a 5-coordinate geometry to one Se(2), two equivalent Se(1), and two equivalent Se(3) atoms. The Tl(1)-Se(2) bond length is 3.47 Å. There is one shorter (3.37 Å) and one longer (3.44 Å) Tl(1)-Se(1) bond length. There is one shorter (3.30 Å) and one longer (3.40 Å) Tl(1)-Se(3) bond length. There are two inequivalent P sites. In the first P site, P(1) is bonded in a distorted tetrahedral geometry to one P(2), one Se(1), one Se(3), and one Se(4) atom. The P(1)-P(2) bond length is 2.27 Å. The P(1)-Se(1) bond length is 2.19 Å. The P(1)-Se(3) bond length is 2.16 Å. The P(1)-Se(4) bond length is 2.26 Å. In the second P site, P(2) is bonded in a distorted tetrahedral geometry to one P(1), one Se(2), one Se(5), and one Se(6) atom. The P(2)-Se(2) bond length is 2.20 Å. The P(2)-Se(5) bond length is 2.24 Å. The P(2)-Se(6) bond length is 2.23 Å. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded in a 2-coordinate geometry to one Sm(1), two equivalent Tl(1), and one P(1) atom. In the second Se site, Se(2) is bonded in a distorted L-shaped geometry to one Sm(1), one Tl(1), and one P(2) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to two equivalent Tl(1) and one P(1) atom. In the fourth Se site, Se(4) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Sm(1) and one P(1) atom. In the fifth Se site, Se(5) is bonded in a distorted T-shaped geometry to two equivalent Sm(1) and one P(2) atom. In the sixth Se site, Se(6) is bonded in a trigonal non-coplanar geometry to two equivalent Sm(1) and one P(2) atom.