Ce3SiO4Cl5 crystallizes in the orthorhombic Pna2_1 space group. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(1), one Cl(3), one Cl(4), two equivalent Cl(1), and three equivalent Cl(5) atoms. In the second Ce site, Ce(2) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(2), one Cl(1), one Cl(4), two equivalent Cl(3), and three equivalent Cl(2) atoms. In the third Ce site, Ce(3) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(3), one Cl(2), one Cl(3), one Cl(5), two equivalent Cl(1), and two equivalent Cl(4) atoms. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ce(1) and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ce(2) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ce(3) and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Ce(1), one Ce(2), one Ce(3), and one Si(1) atom. There are five inequivalent Cl sites. In the first Cl site, Cl(5) is bonded to one Ce(3) and three equivalent Ce(1) atoms to form ClCe4 tetrahedra that share corners with two equivalent Cl(1)Ce5 square pyramids,  a cornercorner with one Cl(2)Ce4 tetrahedra,  a cornercorner with one Cl(4)Ce4 tetrahedra, corners with two equivalent Cl(5)Ce4 tetrahedra, corners with four equivalent Cl(3)Ce4 tetrahedra, edges with three equivalent Cl(1)Ce5 square pyramids, edges with two equivalent Cl(4)Ce4 tetrahedra, and edges with two equivalent Cl(5)Ce4 tetrahedra. In the second Cl site, Cl(1) is bonded to one Ce(2), two equivalent Ce(1), and two equivalent Ce(3) atoms to form distorted ClCe5 square pyramids that share  a cornercorner with one Cl(2)Ce4 tetrahedra, corners with two equivalent Cl(3)Ce4 tetrahedra, corners with two equivalent Cl(5)Ce4 tetrahedra, corners with five equivalent Cl(4)Ce4 tetrahedra, edges with two equivalent Cl(1)Ce5 square pyramids,  an edgeedge with one Cl(4)Ce4 tetrahedra, edges with two equivalent Cl(2)Ce4 tetrahedra, edges with two equivalent Cl(3)Ce4 tetrahedra, and edges with three equivalent Cl(5)Ce4 tetrahedra. In the third Cl site, Cl(2) is bonded to one Ce(3) and three equivalent Ce(2) atoms to form ClCe4 tetrahedra that share  a cornercorner with one Cl(1)Ce5 square pyramid,  a cornercorner with one Cl(5)Ce4 tetrahedra, corners with two equivalent Cl(2)Ce4 tetrahedra, corners with five equivalent Cl(3)Ce4 tetrahedra, corners with five equivalent Cl(4)Ce4 tetrahedra, edges with two equivalent Cl(1)Ce5 square pyramids,  an edgeedge with one Cl(3)Ce4 tetrahedra, and edges with two equivalent Cl(2)Ce4 tetrahedra. In the fourth Cl site, Cl(3) is bonded to one Ce(1), one Ce(3), and two equivalent Ce(2) atoms to form ClCe4 tetrahedra that share corners with two equivalent Cl(1)Ce5 square pyramids,  a cornercorner with one Cl(4)Ce4 tetrahedra, corners with two equivalent Cl(3)Ce4 tetrahedra, corners with four equivalent Cl(5)Ce4 tetrahedra, corners with five equivalent Cl(2)Ce4 tetrahedra, edges with two equivalent Cl(1)Ce5 square pyramids,  an edgeedge with one Cl(2)Ce4 tetrahedra, and edges with two equivalent Cl(4)Ce4 tetrahedra. In the fifth Cl site, Cl(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form distorted ClCe4 tetrahedra that share corners with five equivalent Cl(1)Ce5 square pyramids,  a cornercorner with one Cl(3)Ce4 tetrahedra,  a cornercorner with one Cl(5)Ce4 tetrahedra, corners with two equivalent Cl(4)Ce4 tetrahedra, corners with five equivalent Cl(2)Ce4 tetrahedra,  an edgeedge with one Cl(1)Ce5 square pyramid, edges with two equivalent Cl(3)Ce4 tetrahedra, and edges with two equivalent Cl(5)Ce4 tetrahedra.
Ce3SiO4Cl5 crystallizes in the orthorhombic Pna2_1 space group. There are three inequivalent Ce sites. In the first Ce site, Ce(1) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(1), one Cl(3), one Cl(4), two equivalent Cl(1), and three equivalent Cl(5) atoms. The Ce(1)-O(4) bond length is 2.70 Å. There is one shorter (2.33 Å) and one longer (2.42 Å) Ce(1)-O(1) bond length. The Ce(1)-Cl(3) bond length is 2.91 Å. The Ce(1)-Cl(4) bond length is 2.94 Å. There is one shorter (3.25 Å) and one longer (3.33 Å) Ce(1)-Cl(1) bond length. There are a spread of Ce(1)-Cl(5) bond distances ranging from 3.00-3.14 Å. In the second Ce site, Ce(2) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(2), one Cl(1), one Cl(4), two equivalent Cl(3), and three equivalent Cl(2) atoms. The Ce(2)-O(4) bond length is 2.61 Å. There is one shorter (2.30 Å) and one longer (2.39 Å) Ce(2)-O(2) bond length. The Ce(2)-Cl(1) bond length is 3.60 Å. The Ce(2)-Cl(4) bond length is 2.87 Å. There is one shorter (3.14 Å) and one longer (3.20 Å) Ce(2)-Cl(3) bond length. There are a spread of Ce(2)-Cl(2) bond distances ranging from 2.98-3.16 Å. In the third Ce site, Ce(3) is bonded in a 10-coordinate geometry to one O(4), two equivalent O(3), one Cl(2), one Cl(3), one Cl(5), two equivalent Cl(1), and two equivalent Cl(4) atoms. The Ce(3)-O(4) bond length is 2.62 Å. There is one shorter (2.30 Å) and one longer (2.39 Å) Ce(3)-O(3) bond length. The Ce(3)-Cl(2) bond length is 2.98 Å. The Ce(3)-Cl(3) bond length is 3.08 Å. The Ce(3)-Cl(5) bond length is 3.02 Å. There is one shorter (3.26 Å) and one longer (3.34 Å) Ce(3)-Cl(1) bond length. There is one shorter (3.10 Å) and one longer (3.17 Å) Ce(3)-Cl(4) bond length. Si(1) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(3), and one O(4) atom. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.65 Å. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.67 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ce(1) and one Si(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ce(2) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ce(3) and one Si(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Ce(1), one Ce(2), one Ce(3), and one Si(1) atom. There are five inequivalent Cl sites. In the first Cl site, Cl(5) is bonded to one Ce(3) and three equivalent Ce(1) atoms to form ClCe4 tetrahedra that share corners with two equivalent Cl(1)Ce5 square pyramids,  a cornercorner with one Cl(2)Ce4 tetrahedra,  a cornercorner with one Cl(4)Ce4 tetrahedra, corners with two equivalent Cl(5)Ce4 tetrahedra, corners with four equivalent Cl(3)Ce4 tetrahedra, edges with three equivalent Cl(1)Ce5 square pyramids, edges with two equivalent Cl(4)Ce4 tetrahedra, and edges with two equivalent Cl(5)Ce4 tetrahedra. In the second Cl site, Cl(1) is bonded to one Ce(2), two equivalent Ce(1), and two equivalent Ce(3) atoms to form distorted ClCe5 square pyramids that share  a cornercorner with one Cl(2)Ce4 tetrahedra, corners with two equivalent Cl(3)Ce4 tetrahedra, corners with two equivalent Cl(5)Ce4 tetrahedra, corners with five equivalent Cl(4)Ce4 tetrahedra, edges with two equivalent Cl(1)Ce5 square pyramids,  an edgeedge with one Cl(4)Ce4 tetrahedra, edges with two equivalent Cl(2)Ce4 tetrahedra, edges with two equivalent Cl(3)Ce4 tetrahedra, and edges with three equivalent Cl(5)Ce4 tetrahedra. In the third Cl site, Cl(2) is bonded to one Ce(3) and three equivalent Ce(2) atoms to form ClCe4 tetrahedra that share  a cornercorner with one Cl(1)Ce5 square pyramid,  a cornercorner with one Cl(5)Ce4 tetrahedra, corners with two equivalent Cl(2)Ce4 tetrahedra, corners with five equivalent Cl(3)Ce4 tetrahedra, corners with five equivalent Cl(4)Ce4 tetrahedra, edges with two equivalent Cl(1)Ce5 square pyramids,  an edgeedge with one Cl(3)Ce4 tetrahedra, and edges with two equivalent Cl(2)Ce4 tetrahedra. In the fourth Cl site, Cl(3) is bonded to one Ce(1), one Ce(3), and two equivalent Ce(2) atoms to form ClCe4 tetrahedra that share corners with two equivalent Cl(1)Ce5 square pyramids,  a cornercorner with one Cl(4)Ce4 tetrahedra, corners with two equivalent Cl(3)Ce4 tetrahedra, corners with four equivalent Cl(5)Ce4 tetrahedra, corners with five equivalent Cl(2)Ce4 tetrahedra, edges with two equivalent Cl(1)Ce5 square pyramids,  an edgeedge with one Cl(2)Ce4 tetrahedra, and edges with two equivalent Cl(4)Ce4 tetrahedra. In the fifth Cl site, Cl(4) is bonded to one Ce(1), one Ce(2), and two equivalent Ce(3) atoms to form distorted ClCe4 tetrahedra that share corners with five equivalent Cl(1)Ce5 square pyramids,  a cornercorner with one Cl(3)Ce4 tetrahedra,  a cornercorner with one Cl(5)Ce4 tetrahedra, corners with two equivalent Cl(4)Ce4 tetrahedra, corners with five equivalent Cl(2)Ce4 tetrahedra,  an edgeedge with one Cl(1)Ce5 square pyramid, edges with two equivalent Cl(3)Ce4 tetrahedra, and edges with two equivalent Cl(5)Ce4 tetrahedra.