Na(Ce2Se3)4 crystallizes in the tetragonal I-42d space group. Na(1) is bonded to four equivalent Se(2) and four equivalent Se(3) atoms to form distorted NaSe8 hexagonal bipyramids that share corners with eight equivalent Ce(1)Se8 hexagonal bipyramids, edges with four equivalent Ce(2)Se8 hexagonal bipyramids, faces with four equivalent Ce(1)Se8 hexagonal bipyramids, and faces with four equivalent Ce(3)Se8 hexagonal bipyramids. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to two equivalent Se(2), three equivalent Se(1), and three equivalent Se(3) atoms to form distorted CeSe8 hexagonal bipyramids that share corners with two equivalent Na(1)Se8 hexagonal bipyramids, corners with two equivalent Ce(1)Se8 hexagonal bipyramids, corners with two equivalent Ce(2)Se8 hexagonal bipyramids, corners with two equivalent Ce(3)Se8 hexagonal bipyramids,  an edgeedge with one Ce(3)Se8 hexagonal bipyramid, edges with three equivalent Ce(1)Se8 hexagonal bipyramids,  a faceface with one Na(1)Se8 hexagonal bipyramid, faces with two equivalent Ce(1)Se8 hexagonal bipyramids, faces with two equivalent Ce(3)Se8 hexagonal bipyramids, and faces with three equivalent Ce(2)Se8 hexagonal bipyramids. In the second Ce site, Ce(2) is bonded to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms to form distorted CeSe8 hexagonal bipyramids that share corners with four equivalent Ce(1)Se8 hexagonal bipyramids, corners with four equivalent Ce(3)Se8 hexagonal bipyramids, edges with two equivalent Na(1)Se8 hexagonal bipyramids, edges with two equivalent Ce(2)Se8 hexagonal bipyramids, faces with two equivalent Ce(3)Se8 hexagonal bipyramids, and faces with six equivalent Ce(1)Se8 hexagonal bipyramids. In the third Ce site, Ce(3) is bonded to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms to form distorted CeSe8 hexagonal bipyramids that share corners with four equivalent Ce(1)Se8 hexagonal bipyramids, corners with four equivalent Ce(2)Se8 hexagonal bipyramids, edges with two equivalent Ce(1)Se8 hexagonal bipyramids, edges with two equivalent Ce(3)Se8 hexagonal bipyramids, faces with two equivalent Na(1)Se8 hexagonal bipyramids, faces with two equivalent Ce(2)Se8 hexagonal bipyramids, and faces with four equivalent Ce(1)Se8 hexagonal bipyramids. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ce(3), two equivalent Ce(2), and three equivalent Ce(1) atoms to form distorted SeCe6 octahedra that share corners with three equivalent Se(1)Ce6 octahedra, corners with five equivalent Se(2)NaCe5 octahedra, corners with seven equivalent Se(3)NaCe5 octahedra,  an edgeedge with one Se(3)NaCe5 octahedra, edges with two equivalent Se(1)Ce6 octahedra, edges with three equivalent Se(2)NaCe5 octahedra,  a faceface with one Se(2)NaCe5 octahedra, faces with two equivalent Se(1)Ce6 octahedra, and faces with two equivalent Se(3)NaCe5 octahedra. The corner-sharing octahedral tilt angles range from 15-51°. In the second Se site, Se(2) is bonded to one Na(1), one Ce(2), two equivalent Ce(1), and two equivalent Ce(3) atoms to form distorted SeNaCe5 octahedra that share corners with four equivalent Se(3)NaCe5 octahedra, corners with five equivalent Se(1)Ce6 octahedra, corners with six equivalent Se(2)NaCe5 octahedra, edges with three equivalent Se(1)Ce6 octahedra, edges with three equivalent Se(3)NaCe5 octahedra,  a faceface with one Se(1)Ce6 octahedra, faces with two equivalent Se(2)NaCe5 octahedra, and faces with two equivalent Se(3)NaCe5 octahedra. The corner-sharing octahedral tilt angles range from 19-50°. In the third Se site, Se(3) is bonded to one Na(1), one Ce(2), one Ce(3), and three equivalent Ce(1) atoms to form distorted SeNaCe5 octahedra that share corners with four equivalent Se(2)NaCe5 octahedra, corners with four equivalent Se(3)NaCe5 octahedra, corners with seven equivalent Se(1)Ce6 octahedra,  an edgeedge with one Se(1)Ce6 octahedra, edges with two equivalent Se(3)NaCe5 octahedra, edges with three equivalent Se(2)NaCe5 octahedra,  a faceface with one Se(3)NaCe5 octahedra, faces with two equivalent Se(1)Ce6 octahedra, and faces with two equivalent Se(2)NaCe5 octahedra. The corner-sharing octahedral tilt angles range from 15-51°.
Na(Ce2Se3)4 crystallizes in the tetragonal I-42d space group. Na(1) is bonded to four equivalent Se(2) and four equivalent Se(3) atoms to form distorted NaSe8 hexagonal bipyramids that share corners with eight equivalent Ce(1)Se8 hexagonal bipyramids, edges with four equivalent Ce(2)Se8 hexagonal bipyramids, faces with four equivalent Ce(1)Se8 hexagonal bipyramids, and faces with four equivalent Ce(3)Se8 hexagonal bipyramids. All Na(1)-Se(2) bond lengths are 3.27 Å. All Na(1)-Se(3) bond lengths are 3.03 Å. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded to two equivalent Se(2), three equivalent Se(1), and three equivalent Se(3) atoms to form distorted CeSe8 hexagonal bipyramids that share corners with two equivalent Na(1)Se8 hexagonal bipyramids, corners with two equivalent Ce(1)Se8 hexagonal bipyramids, corners with two equivalent Ce(2)Se8 hexagonal bipyramids, corners with two equivalent Ce(3)Se8 hexagonal bipyramids,  an edgeedge with one Ce(3)Se8 hexagonal bipyramid, edges with three equivalent Ce(1)Se8 hexagonal bipyramids,  a faceface with one Na(1)Se8 hexagonal bipyramid, faces with two equivalent Ce(1)Se8 hexagonal bipyramids, faces with two equivalent Ce(3)Se8 hexagonal bipyramids, and faces with three equivalent Ce(2)Se8 hexagonal bipyramids. There is one shorter (2.98 Å) and one longer (3.19 Å) Ce(1)-Se(2) bond length. There are a spread of Ce(1)-Se(1) bond distances ranging from 3.01-3.22 Å. There are a spread of Ce(1)-Se(3) bond distances ranging from 3.01-3.17 Å. In the second Ce site, Ce(2) is bonded to two equivalent Se(2), two equivalent Se(3), and four equivalent Se(1) atoms to form distorted CeSe8 hexagonal bipyramids that share corners with four equivalent Ce(1)Se8 hexagonal bipyramids, corners with four equivalent Ce(3)Se8 hexagonal bipyramids, edges with two equivalent Na(1)Se8 hexagonal bipyramids, edges with two equivalent Ce(2)Se8 hexagonal bipyramids, faces with two equivalent Ce(3)Se8 hexagonal bipyramids, and faces with six equivalent Ce(1)Se8 hexagonal bipyramids. Both Ce(2)-Se(2) bond lengths are 2.98 Å. Both Ce(2)-Se(3) bond lengths are 3.17 Å. There are two shorter (3.02 Å) and two longer (3.17 Å) Ce(2)-Se(1) bond lengths. In the third Ce site, Ce(3) is bonded to two equivalent Se(1), two equivalent Se(3), and four equivalent Se(2) atoms to form distorted CeSe8 hexagonal bipyramids that share corners with four equivalent Ce(1)Se8 hexagonal bipyramids, corners with four equivalent Ce(2)Se8 hexagonal bipyramids, edges with two equivalent Ce(1)Se8 hexagonal bipyramids, edges with two equivalent Ce(3)Se8 hexagonal bipyramids, faces with two equivalent Na(1)Se8 hexagonal bipyramids, faces with two equivalent Ce(2)Se8 hexagonal bipyramids, and faces with four equivalent Ce(1)Se8 hexagonal bipyramids. Both Ce(3)-Se(1) bond lengths are 3.20 Å. Both Ce(3)-Se(3) bond lengths are 3.03 Å. There are two shorter (3.01 Å) and two longer (3.17 Å) Ce(3)-Se(2) bond lengths. There are three inequivalent Se sites. In the first Se site, Se(1) is bonded to one Ce(3), two equivalent Ce(2), and three equivalent Ce(1) atoms to form distorted SeCe6 octahedra that share corners with three equivalent Se(1)Ce6 octahedra, corners with five equivalent Se(2)NaCe5 octahedra, corners with seven equivalent Se(3)NaCe5 octahedra,  an edgeedge with one Se(3)NaCe5 octahedra, edges with two equivalent Se(1)Ce6 octahedra, edges with three equivalent Se(2)NaCe5 octahedra,  a faceface with one Se(2)NaCe5 octahedra, faces with two equivalent Se(1)Ce6 octahedra, and faces with two equivalent Se(3)NaCe5 octahedra. The corner-sharing octahedral tilt angles range from 15-51°. In the second Se site, Se(2) is bonded to one Na(1), one Ce(2), two equivalent Ce(1), and two equivalent Ce(3) atoms to form distorted SeNaCe5 octahedra that share corners with four equivalent Se(3)NaCe5 octahedra, corners with five equivalent Se(1)Ce6 octahedra, corners with six equivalent Se(2)NaCe5 octahedra, edges with three equivalent Se(1)Ce6 octahedra, edges with three equivalent Se(3)NaCe5 octahedra,  a faceface with one Se(1)Ce6 octahedra, faces with two equivalent Se(2)NaCe5 octahedra, and faces with two equivalent Se(3)NaCe5 octahedra. The corner-sharing octahedral tilt angles range from 19-50°. In the third Se site, Se(3) is bonded to one Na(1), one Ce(2), one Ce(3), and three equivalent Ce(1) atoms to form distorted SeNaCe5 octahedra that share corners with four equivalent Se(2)NaCe5 octahedra, corners with four equivalent Se(3)NaCe5 octahedra, corners with seven equivalent Se(1)Ce6 octahedra,  an edgeedge with one Se(1)Ce6 octahedra, edges with two equivalent Se(3)NaCe5 octahedra, edges with three equivalent Se(2)NaCe5 octahedra,  a faceface with one Se(3)NaCe5 octahedra, faces with two equivalent Se(1)Ce6 octahedra, and faces with two equivalent Se(2)NaCe5 octahedra. The corner-sharing octahedral tilt angles range from 15-51°.