CeSe2 is Low Tridymite-like structured and crystallizes in the monoclinic C2/m space group. There are seven inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form corner-sharing CeSe4 tetrahedra. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(2), and two equivalent Se(5) atoms to form corner-sharing CeSe4 tetrahedra. In the third Ce site, Ce(3) is bonded to one Se(4), one Se(6), and two equivalent Se(3) atoms to form corner-sharing CeSe4 tetrahedra. In the fourth Ce site, Ce(4) is bonded to one Se(10), one Se(9), and two equivalent Se(5) atoms to form corner-sharing CeSe4 tetrahedra. In the fifth Ce site, Ce(5) is bonded to one Se(10), one Se(4), and two equivalent Se(8) atoms to form corner-sharing CeSe4 tetrahedra. In the sixth Ce site, Ce(6) is bonded to one Se(11), one Se(9), and two equivalent Se(8) atoms to form corner-sharing CeSe4 tetrahedra. In the seventh Ce site, Ce(7) is bonded to one Se(11), one Se(6), and two equivalent Se(7) atoms to form corner-sharing CeSe4 tetrahedra. There are eleven inequivalent Se sites. In the first Se site, Se(3) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(3) atom. In the second Se site, Se(4) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(5) atom. In the third Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(4) atom. In the fourth Se site, Se(6) is bonded in a bent 120 degrees geometry to one Ce(3) and one Ce(7) atom. In the fifth Se site, Se(7) is bonded in a linear geometry to two equivalent Ce(7) atoms. In the sixth Se site, Se(8) is bonded in a bent 150 degrees geometry to one Ce(5) and one Ce(6) atom. In the seventh Se site, Se(9) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(6) atom. In the eighth Se site, Se(10) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(5) atom. In the ninth Se site, Se(11) is bonded in a linear geometry to one Ce(6) and one Ce(7) atom. In the tenth Se site, Se(1) is bonded in a bent 120 degrees geometry to one Ce(1) and one Ce(2) atom. In the eleventh Se site, Se(2) is bonded in a linear geometry to one Ce(1) and one Ce(2) atom.
CeSe2 is Low Tridymite-like structured and crystallizes in the monoclinic C2/m space group. There are seven inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to one Se(1), one Se(2), and two equivalent Se(3) atoms to form corner-sharing CeSe4 tetrahedra. The Ce(1)-Se(1) bond length is 2.73 Å. The Ce(1)-Se(2) bond length is 2.70 Å. Both Ce(1)-Se(3) bond lengths are 2.72 Å. In the second Ce site, Ce(2) is bonded to one Se(1), one Se(2), and two equivalent Se(5) atoms to form corner-sharing CeSe4 tetrahedra. The Ce(2)-Se(1) bond length is 2.73 Å. The Ce(2)-Se(2) bond length is 2.72 Å. Both Ce(2)-Se(5) bond lengths are 2.72 Å. In the third Ce site, Ce(3) is bonded to one Se(4), one Se(6), and two equivalent Se(3) atoms to form corner-sharing CeSe4 tetrahedra. The Ce(3)-Se(4) bond length is 2.73 Å. The Ce(3)-Se(6) bond length is 2.72 Å. Both Ce(3)-Se(3) bond lengths are 2.71 Å. In the fourth Ce site, Ce(4) is bonded to one Se(10), one Se(9), and two equivalent Se(5) atoms to form corner-sharing CeSe4 tetrahedra. The Ce(4)-Se(10) bond length is 2.71 Å. The Ce(4)-Se(9) bond length is 2.73 Å. Both Ce(4)-Se(5) bond lengths are 2.72 Å. In the fifth Ce site, Ce(5) is bonded to one Se(10), one Se(4), and two equivalent Se(8) atoms to form corner-sharing CeSe4 tetrahedra. The Ce(5)-Se(10) bond length is 2.71 Å. The Ce(5)-Se(4) bond length is 2.71 Å. Both Ce(5)-Se(8) bond lengths are 2.72 Å. In the sixth Ce site, Ce(6) is bonded to one Se(11), one Se(9), and two equivalent Se(8) atoms to form corner-sharing CeSe4 tetrahedra. The Ce(6)-Se(11) bond length is 2.72 Å. The Ce(6)-Se(9) bond length is 2.71 Å. Both Ce(6)-Se(8) bond lengths are 2.71 Å. In the seventh Ce site, Ce(7) is bonded to one Se(11), one Se(6), and two equivalent Se(7) atoms to form corner-sharing CeSe4 tetrahedra. The Ce(7)-Se(11) bond length is 2.71 Å. The Ce(7)-Se(6) bond length is 2.72 Å. Both Ce(7)-Se(7) bond lengths are 2.71 Å. There are eleven inequivalent Se sites. In the first Se site, Se(3) is bonded in a bent 150 degrees geometry to one Ce(1) and one Ce(3) atom. In the second Se site, Se(4) is bonded in a bent 150 degrees geometry to one Ce(3) and one Ce(5) atom. In the third Se site, Se(5) is bonded in a bent 150 degrees geometry to one Ce(2) and one Ce(4) atom. In the fourth Se site, Se(6) is bonded in a bent 120 degrees geometry to one Ce(3) and one Ce(7) atom. In the fifth Se site, Se(7) is bonded in a linear geometry to two equivalent Ce(7) atoms. In the sixth Se site, Se(8) is bonded in a bent 150 degrees geometry to one Ce(5) and one Ce(6) atom. In the seventh Se site, Se(9) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(6) atom. In the eighth Se site, Se(10) is bonded in a bent 150 degrees geometry to one Ce(4) and one Ce(5) atom. In the ninth Se site, Se(11) is bonded in a linear geometry to one Ce(6) and one Ce(7) atom. In the tenth Se site, Se(1) is bonded in a bent 120 degrees geometry to one Ce(1) and one Ce(2) atom. In the eleventh Se site, Se(2) is bonded in a linear geometry to one Ce(1) and one Ce(2) atom.