Ce3Si6N11 crystallizes in the tetragonal P4bm space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 8-coordinate geometry to one N(2), one N(4), two equivalent N(3), and four equivalent N(1) atoms. In the second Ce site, Ce(2) is bonded in a 8-coordinate geometry to four equivalent N(1) and four equivalent N(3) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form corner-sharing SiN4 tetrahedra. In the second Si site, Si(2) is bonded to one N(2), one N(4), and two equivalent N(1) atoms to form corner-sharing SiN4 tetrahedra. There are four inequivalent N sites. In the first N site, N(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ce(1) and two equivalent Si(2) atoms. In the second N site, N(1) is bonded in a 2-coordinate geometry to one Ce(2), two equivalent Ce(1), one Si(1), and one Si(2) atom. In the third N site, N(2) is bonded in a trigonal planar geometry to one Ce(1), one Si(2), and two equivalent Si(1) atoms. In the fourth N site, N(3) is bonded to one Ce(1), one Ce(2), and two equivalent Si(1) atoms to form a mixture of distorted edge and corner-sharing NCe2Si2 trigonal pyramids.
Ce3Si6N11 crystallizes in the tetragonal P4bm space group. There are two inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 8-coordinate geometry to one N(2), one N(4), two equivalent N(3), and four equivalent N(1) atoms. The Ce(1)-N(2) bond length is 2.80 Å. The Ce(1)-N(4) bond length is 2.60 Å. Both Ce(1)-N(3) bond lengths are 2.47 Å. There are two shorter (2.68 Å) and two longer (2.87 Å) Ce(1)-N(1) bond lengths. In the second Ce site, Ce(2) is bonded in a 8-coordinate geometry to four equivalent N(1) and four equivalent N(3) atoms. All Ce(2)-N(1) bond lengths are 2.62 Å. All Ce(2)-N(3) bond lengths are 2.62 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one N(1), one N(2), and two equivalent N(3) atoms to form corner-sharing SiN4 tetrahedra. The Si(1)-N(1) bond length is 1.73 Å. The Si(1)-N(2) bond length is 1.77 Å. There is one shorter (1.72 Å) and one longer (1.74 Å) Si(1)-N(3) bond length. In the second Si site, Si(2) is bonded to one N(2), one N(4), and two equivalent N(1) atoms to form corner-sharing SiN4 tetrahedra. The Si(2)-N(2) bond length is 1.76 Å. The Si(2)-N(4) bond length is 1.69 Å. Both Si(2)-N(1) bond lengths are 1.73 Å. There are four inequivalent N sites. In the first N site, N(4) is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ce(1) and two equivalent Si(2) atoms. In the second N site, N(1) is bonded in a 2-coordinate geometry to one Ce(2), two equivalent Ce(1), one Si(1), and one Si(2) atom. In the third N site, N(2) is bonded in a trigonal planar geometry to one Ce(1), one Si(2), and two equivalent Si(1) atoms. In the fourth N site, N(3) is bonded to one Ce(1), one Ce(2), and two equivalent Si(1) atoms to form a mixture of distorted edge and corner-sharing NCe2Si2 trigonal pyramids.