CeCrSe2O crystallizes in the monoclinic C2/m space group. Ce(1) is bonded in a 3-coordinate geometry to three equivalent Se(1), three equivalent Se(2), and three equivalent O(1) atoms. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form CrSe6 octahedra that share corners with four equivalent Cr(2)Se4O2 octahedra and edges with two equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 55°. In the second Cr site, Cr(2) is bonded to four equivalent Se(2) and two equivalent O(1) atoms to form distorted CrSe4O2 octahedra that share corners with four equivalent Cr(1)Se6 octahedra and edges with two equivalent Cr(2)Se4O2 octahedra. The corner-sharing octahedral tilt angles are 55°. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to three equivalent Ce(1) and two equivalent Cr(1) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Ce(1), one Cr(1), and two equivalent Cr(2) atoms. O(1) is bonded to three equivalent Ce(1) and one Cr(2) atom to form a mixture of corner and edge-sharing OCe3Cr tetrahedra.
CeCrSe2O crystallizes in the monoclinic C2/m space group. Ce(1) is bonded in a 3-coordinate geometry to three equivalent Se(1), three equivalent Se(2), and three equivalent O(1) atoms. There are two shorter (3.16 Å) and one longer (3.25 Å) Ce(1)-Se(1) bond length. There are two shorter (3.21 Å) and one longer (3.24 Å) Ce(1)-Se(2) bond length. There are two shorter (2.33 Å) and one longer (2.42 Å) Ce(1)-O(1) bond length. There are two inequivalent Cr sites. In the first Cr site, Cr(1) is bonded to two equivalent Se(2) and four equivalent Se(1) atoms to form CrSe6 octahedra that share corners with four equivalent Cr(2)Se4O2 octahedra and edges with two equivalent Cr(1)Se6 octahedra. The corner-sharing octahedral tilt angles are 55°. Both Cr(1)-Se(2) bond lengths are 2.57 Å. All Cr(1)-Se(1) bond lengths are 2.60 Å. In the second Cr site, Cr(2) is bonded to four equivalent Se(2) and two equivalent O(1) atoms to form distorted CrSe4O2 octahedra that share corners with four equivalent Cr(1)Se6 octahedra and edges with two equivalent Cr(2)Se4O2 octahedra. The corner-sharing octahedral tilt angles are 55°. All Cr(2)-Se(2) bond lengths are 2.67 Å. Both Cr(2)-O(1) bond lengths are 2.06 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to three equivalent Ce(1) and two equivalent Cr(1) atoms. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to three equivalent Ce(1), one Cr(1), and two equivalent Cr(2) atoms. O(1) is bonded to three equivalent Ce(1) and one Cr(2) atom to form a mixture of corner and edge-sharing OCe3Cr tetrahedra.