Cs2(MoO3)3SeO3 crystallizes in the hexagonal P6_3 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 6-coordinate geometry to three equivalent O(2) and three equivalent O(4) atoms. In the second Cs site, Cs(2) is bonded in a 15-coordinate geometry to three equivalent O(1), three equivalent O(2), three equivalent O(3), and six equivalent O(4) atoms. Mo(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 31-44°. Se(1) is bonded in a trigonal non-coplanar geometry to three equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Cs(2), one Mo(1), and one Se(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(2), and two equivalent Mo(1) atoms. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cs(2) and two equivalent Mo(1) atoms. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Cs(1), two equivalent Cs(2), and one Mo(1) atom.
Cs2(MoO3)3SeO3 crystallizes in the hexagonal P6_3 space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 6-coordinate geometry to three equivalent O(2) and three equivalent O(4) atoms. All Cs(1)-O(2) bond lengths are 3.08 Å. All Cs(1)-O(4) bond lengths are 3.05 Å. In the second Cs site, Cs(2) is bonded in a 15-coordinate geometry to three equivalent O(1), three equivalent O(2), three equivalent O(3), and six equivalent O(4) atoms. All Cs(2)-O(1) bond lengths are 3.14 Å. All Cs(2)-O(2) bond lengths are 3.54 Å. All Cs(2)-O(3) bond lengths are 3.55 Å. All Cs(2)-O(4) bond lengths are 3.79 Å. Mo(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted corner-sharing MoO6 octahedra. The corner-sharing octahedral tilt angles range from 31-44°. The Mo(1)-O(1) bond length is 2.17 Å. The Mo(1)-O(4) bond length is 1.71 Å. There is one shorter (1.80 Å) and one longer (2.11 Å) Mo(1)-O(2) bond length. There is one shorter (1.79 Å) and one longer (2.10 Å) Mo(1)-O(3) bond length. Se(1) is bonded in a trigonal non-coplanar geometry to three equivalent O(1) atoms. All Se(1)-O(1) bond lengths are 1.72 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Cs(2), one Mo(1), and one Se(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Cs(1), one Cs(2), and two equivalent Mo(1) atoms. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to one Cs(2) and two equivalent Mo(1) atoms. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Cs(1), two equivalent Cs(2), and one Mo(1) atom.