CeSe2 crystallizes in the orthorhombic Pmc2_1 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 8-coordinate geometry to one Se(3), one Se(4), two equivalent Se(2), two equivalent Se(5), and two equivalent Se(6) atoms. In the second Ce site, Ce(2) is bonded in a 8-coordinate geometry to one Se(3), one Se(4), two equivalent Se(1), two equivalent Se(5), and two equivalent Se(6) atoms. In the third Ce site, Ce(3) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms. In the fourth Ce site, Ce(4) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(5), and two equivalent Se(6) atoms. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(2) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the second Se site, Se(2) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(1) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the third Se site, Se(3) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(4) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the fourth Se site, Se(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the fifth Se site, Se(5) is bonded in a 6-coordinate geometry to one Ce(1), one Ce(2), one Ce(3), one Ce(4), and two equivalent Se(5) atoms. In the sixth Se site, Se(6) is bonded in a 6-coordinate geometry to one Ce(1), one Ce(2), one Ce(3), one Ce(4), and two equivalent Se(6) atoms.
CeSe2 crystallizes in the orthorhombic Pmc2_1 space group. There are four inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 8-coordinate geometry to one Se(3), one Se(4), two equivalent Se(2), two equivalent Se(5), and two equivalent Se(6) atoms. The Ce(1)-Se(3) bond length is 2.93 Å. The Ce(1)-Se(4) bond length is 2.89 Å. Both Ce(1)-Se(2) bond lengths are 3.00 Å. Both Ce(1)-Se(5) bond lengths are 3.09 Å. Both Ce(1)-Se(6) bond lengths are 3.00 Å. In the second Ce site, Ce(2) is bonded in a 8-coordinate geometry to one Se(3), one Se(4), two equivalent Se(1), two equivalent Se(5), and two equivalent Se(6) atoms. The Ce(2)-Se(3) bond length is 2.93 Å. The Ce(2)-Se(4) bond length is 2.91 Å. Both Ce(2)-Se(1) bond lengths are 2.99 Å. Both Ce(2)-Se(5) bond lengths are 3.25 Å. Both Ce(2)-Se(6) bond lengths are 3.13 Å. In the third Ce site, Ce(3) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(4), two equivalent Se(5), and two equivalent Se(6) atoms. The Ce(3)-Se(1) bond length is 3.02 Å. The Ce(3)-Se(2) bond length is 2.96 Å. Both Ce(3)-Se(4) bond lengths are 3.01 Å. Both Ce(3)-Se(5) bond lengths are 3.05 Å. Both Ce(3)-Se(6) bond lengths are 3.16 Å. In the fourth Ce site, Ce(4) is bonded in a 8-coordinate geometry to one Se(1), one Se(2), two equivalent Se(3), two equivalent Se(5), and two equivalent Se(6) atoms. The Ce(4)-Se(1) bond length is 2.92 Å. The Ce(4)-Se(2) bond length is 2.93 Å. Both Ce(4)-Se(3) bond lengths are 2.99 Å. Both Ce(4)-Se(5) bond lengths are 2.99 Å. Both Ce(4)-Se(6) bond lengths are 3.06 Å. There are six inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(2) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the second Se site, Se(2) is bonded to one Ce(3), one Ce(4), and two equivalent Ce(1) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the third Se site, Se(3) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(4) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the fourth Se site, Se(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form a mixture of distorted edge and corner-sharing SeCe4 trigonal pyramids. In the fifth Se site, Se(5) is bonded in a 6-coordinate geometry to one Ce(1), one Ce(2), one Ce(3), one Ce(4), and two equivalent Se(5) atoms. There is one shorter (2.77 Å) and one longer (2.87 Å) Se(5)-Se(5) bond length. In the sixth Se site, Se(6) is bonded in a 6-coordinate geometry to one Ce(1), one Ce(2), one Ce(3), one Ce(4), and two equivalent Se(6) atoms. There is one shorter (2.78 Å) and one longer (2.86 Å) Se(6)-Se(6) bond length.