CsPbPSe4 crystallizes in the orthorhombic Pnma space group. Cs(1) is bonded in a 9-coordinate geometry to one Se(3), four equivalent Se(1), and four equivalent Se(2) atoms. Pb(1) is bonded in a 6-coordinate geometry to one Se(1), one Se(3), and four equivalent Se(2) atoms. P(1) is bonded in a tetrahedral geometry to one Se(1), one Se(3), and two equivalent Se(2) atoms. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 1-coordinate geometry to four equivalent Cs(1), one Pb(1), and one P(1) atom. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1), two equivalent Pb(1), and one P(1) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Cs(1), one Pb(1), and one P(1) atom.
CsPbPSe4 crystallizes in the orthorhombic Pnma space group. Cs(1) is bonded in a 9-coordinate geometry to one Se(3), four equivalent Se(1), and four equivalent Se(2) atoms. The Cs(1)-Se(3) bond length is 3.60 Å. There are a spread of Cs(1)-Se(1) bond distances ranging from 3.73-4.26 Å. There are two shorter (3.79 Å) and two longer (3.95 Å) Cs(1)-Se(2) bond lengths. Pb(1) is bonded in a 6-coordinate geometry to one Se(1), one Se(3), and four equivalent Se(2) atoms. The Pb(1)-Se(1) bond length is 3.09 Å. The Pb(1)-Se(3) bond length is 3.06 Å. There are two shorter (3.22 Å) and two longer (3.31 Å) Pb(1)-Se(2) bond lengths. P(1) is bonded in a tetrahedral geometry to one Se(1), one Se(3), and two equivalent Se(2) atoms. The P(1)-Se(1) bond length is 2.21 Å. The P(1)-Se(3) bond length is 2.22 Å. Both P(1)-Se(2) bond lengths are 2.22 Å. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded in a 1-coordinate geometry to four equivalent Cs(1), one Pb(1), and one P(1) atom. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1), two equivalent Pb(1), and one P(1) atom. In the third Se site, Se(3) is bonded in a distorted T-shaped geometry to one Cs(1), one Pb(1), and one P(1) atom.