SnPSe3 crystallizes in the monoclinic P2_1/c space group. Sn(1) is bonded in a 4-coordinate geometry to one P(1), one Se(2), and two equivalent Se(1) atoms. P(1) is bonded in a 4-coordinate geometry to one Sn(1), one P(1), one Se(2), and one Se(3) atom. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to two equivalent Sn(1) and one Se(3) atom. In the second Se site, Se(2) is bonded in a distorted water-like geometry to one Sn(1) and one P(1) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to one P(1) and one Se(1) atom.
SnPSe3 crystallizes in the monoclinic P2_1/c space group. Sn(1) is bonded in a 4-coordinate geometry to one P(1), one Se(2), and two equivalent Se(1) atoms. The Sn(1)-P(1) bond length is 2.85 Å. The Sn(1)-Se(2) bond length is 2.94 Å. There is one shorter (2.77 Å) and one longer (3.21 Å) Sn(1)-Se(1) bond length. P(1) is bonded in a 4-coordinate geometry to one Sn(1), one P(1), one Se(2), and one Se(3) atom. The P(1)-P(1) bond length is 2.29 Å. The P(1)-Se(2) bond length is 2.23 Å. The P(1)-Se(3) bond length is 2.32 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 3-coordinate geometry to two equivalent Sn(1) and one Se(3) atom. The Se(1)-Se(3) bond length is 2.37 Å. In the second Se site, Se(2) is bonded in a distorted water-like geometry to one Sn(1) and one P(1) atom. In the third Se site, Se(3) is bonded in a distorted single-bond geometry to one P(1) and one Se(1) atom.