Cs3P(SeO6)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 11-coordinate geometry to one O(2), one O(5), one O(6), two equivalent O(3), three equivalent O(1), and three equivalent O(4) atoms. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent O(3), two equivalent O(5), two equivalent O(6), and four equivalent O(2) atoms. P(1) is bonded in a tetrahedral geometry to two equivalent O(5) and two equivalent O(6) atoms. Se(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are six inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to one Cs(2), two equivalent Cs(1), and one Se(1) atom. In the second O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Se(1) atom. In the third O site, O(5) is bonded in a single-bond geometry to one Cs(1), one Cs(2), and one P(1) atom. In the fourth O site, O(6) is bonded in a single-bond geometry to one Cs(1), one Cs(2), and one P(1) atom. In the fifth O site, O(1) is bonded in a single-bond geometry to three equivalent Cs(1) and one Se(1) atom. In the sixth O site, O(2) is bonded in a distorted single-bond geometry to one Cs(1), two equivalent Cs(2), and one Se(1) atom.
Cs3P(SeO6)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 11-coordinate geometry to one O(2), one O(5), one O(6), two equivalent O(3), three equivalent O(1), and three equivalent O(4) atoms. The Cs(1)-O(2) bond length is 3.46 Å. The Cs(1)-O(5) bond length is 3.24 Å. The Cs(1)-O(6) bond length is 3.27 Å. There is one shorter (3.26 Å) and one longer (3.45 Å) Cs(1)-O(3) bond length. There are a spread of Cs(1)-O(1) bond distances ranging from 3.32-3.69 Å. There are a spread of Cs(1)-O(4) bond distances ranging from 3.20-3.50 Å. In the second Cs site, Cs(2) is bonded in a 10-coordinate geometry to two equivalent O(3), two equivalent O(5), two equivalent O(6), and four equivalent O(2) atoms. Both Cs(2)-O(3) bond lengths are 3.47 Å. Both Cs(2)-O(5) bond lengths are 3.33 Å. Both Cs(2)-O(6) bond lengths are 3.44 Å. There are two shorter (3.08 Å) and two longer (3.25 Å) Cs(2)-O(2) bond lengths. P(1) is bonded in a tetrahedral geometry to two equivalent O(5) and two equivalent O(6) atoms. Both P(1)-O(5) bond lengths are 1.54 Å. Both P(1)-O(6) bond lengths are 1.55 Å. Se(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Se(1)-O(1) bond length is 1.68 Å. The Se(1)-O(2) bond length is 1.68 Å. The Se(1)-O(3) bond length is 1.68 Å. The Se(1)-O(4) bond length is 1.68 Å. There are six inequivalent O sites. In the first O site, O(3) is bonded in a distorted single-bond geometry to one Cs(2), two equivalent Cs(1), and one Se(1) atom. In the second O site, O(4) is bonded in a distorted single-bond geometry to three equivalent Cs(1) and one Se(1) atom. In the third O site, O(5) is bonded in a single-bond geometry to one Cs(1), one Cs(2), and one P(1) atom. In the fourth O site, O(6) is bonded in a single-bond geometry to one Cs(1), one Cs(2), and one P(1) atom. In the fifth O site, O(1) is bonded in a single-bond geometry to three equivalent Cs(1) and one Se(1) atom. In the sixth O site, O(2) is bonded in a distorted single-bond geometry to one Cs(1), two equivalent Cs(2), and one Se(1) atom.