Cd2SiO4 crystallizes in the triclinic P1 space group. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(4)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(2)O6 pentagonal pyramids, edges with two equivalent Cd(3)O6 pentagonal pyramids, and  an edgeedge with one Si(1)O4 tetrahedra. In the second Cd site, Cd(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(3)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(1)O6 pentagonal pyramids, edges with two equivalent Cd(4)O6 pentagonal pyramids, and  an edgeedge with one Si(1)O4 tetrahedra. In the third Cd site, Cd(3) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(2)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(1)O6 pentagonal pyramids, edges with two equivalent Cd(4)O6 pentagonal pyramids, and  an edgeedge with one Si(2)O4 tetrahedra. In the fourth Cd site, Cd(4) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(1)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(2)O6 pentagonal pyramids, edges with two equivalent Cd(3)O6 pentagonal pyramids, and  an edgeedge with one Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Cd(1)O6 pentagonal pyramids, corners with two equivalent Cd(2)O6 pentagonal pyramids, corners with two equivalent Cd(3)O6 pentagonal pyramids, corners with two equivalent Cd(4)O6 pentagonal pyramids,  an edgeedge with one Cd(1)O6 pentagonal pyramid, and  an edgeedge with one Cd(2)O6 pentagonal pyramid. In the second Si site, Si(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Cd(1)O6 pentagonal pyramids, corners with two equivalent Cd(2)O6 pentagonal pyramids, corners with two equivalent Cd(3)O6 pentagonal pyramids, corners with two equivalent Cd(4)O6 pentagonal pyramids,  an edgeedge with one Cd(3)O6 pentagonal pyramid, and  an edgeedge with one Cd(4)O6 pentagonal pyramid. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(4), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(3), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(4), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(3), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Cd(2), one Cd(3), one Cd(4), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(3), one Cd(4), and one Si(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(3), one Cd(4), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Cd(2), one Cd(3), one Cd(4), and one Si(2) atom.
Cd2SiO4 crystallizes in the triclinic P1 space group. There are four inequivalent Cd sites. In the first Cd site, Cd(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(4)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(2)O6 pentagonal pyramids, edges with two equivalent Cd(3)O6 pentagonal pyramids, and  an edgeedge with one Si(1)O4 tetrahedra. The Cd(1)-O(1) bond length is 2.43 Å. The Cd(1)-O(2) bond length is 2.47 Å. The Cd(1)-O(3) bond length is 2.51 Å. The Cd(1)-O(4) bond length is 2.42 Å. The Cd(1)-O(6) bond length is 2.22 Å. The Cd(1)-O(7) bond length is 2.26 Å. In the second Cd site, Cd(2) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(8) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(3)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(1)O6 pentagonal pyramids, edges with two equivalent Cd(4)O6 pentagonal pyramids, and  an edgeedge with one Si(1)O4 tetrahedra. The Cd(2)-O(1) bond length is 2.39 Å. The Cd(2)-O(2) bond length is 2.53 Å. The Cd(2)-O(3) bond length is 2.43 Å. The Cd(2)-O(4) bond length is 2.50 Å. The Cd(2)-O(5) bond length is 2.21 Å. The Cd(2)-O(8) bond length is 2.30 Å. In the third Cd site, Cd(3) is bonded to one O(2), one O(4), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(2)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(1)O6 pentagonal pyramids, edges with two equivalent Cd(4)O6 pentagonal pyramids, and  an edgeedge with one Si(2)O4 tetrahedra. The Cd(3)-O(2) bond length is 2.20 Å. The Cd(3)-O(4) bond length is 2.32 Å. The Cd(3)-O(5) bond length is 2.49 Å. The Cd(3)-O(6) bond length is 2.44 Å. The Cd(3)-O(7) bond length is 2.40 Å. The Cd(3)-O(8) bond length is 2.46 Å. In the fourth Cd site, Cd(4) is bonded to one O(1), one O(3), one O(5), one O(6), one O(7), and one O(8) atom to form distorted CdO6 pentagonal pyramids that share corners with four equivalent Cd(1)O6 pentagonal pyramids, corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Cd(2)O6 pentagonal pyramids, edges with two equivalent Cd(3)O6 pentagonal pyramids, and  an edgeedge with one Si(2)O4 tetrahedra. The Cd(4)-O(1) bond length is 2.28 Å. The Cd(4)-O(3) bond length is 2.16 Å. The Cd(4)-O(5) bond length is 2.44 Å. The Cd(4)-O(6) bond length is 2.49 Å. The Cd(4)-O(7) bond length is 2.52 Å. The Cd(4)-O(8) bond length is 2.46 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with two equivalent Cd(1)O6 pentagonal pyramids, corners with two equivalent Cd(2)O6 pentagonal pyramids, corners with two equivalent Cd(3)O6 pentagonal pyramids, corners with two equivalent Cd(4)O6 pentagonal pyramids,  an edgeedge with one Cd(1)O6 pentagonal pyramid, and  an edgeedge with one Cd(2)O6 pentagonal pyramid. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.62 Å. The Si(1)-O(3) bond length is 1.70 Å. The Si(1)-O(4) bond length is 1.58 Å. In the second Si site, Si(2) is bonded to one O(5), one O(6), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Cd(1)O6 pentagonal pyramids, corners with two equivalent Cd(2)O6 pentagonal pyramids, corners with two equivalent Cd(3)O6 pentagonal pyramids, corners with two equivalent Cd(4)O6 pentagonal pyramids,  an edgeedge with one Cd(3)O6 pentagonal pyramid, and  an edgeedge with one Cd(4)O6 pentagonal pyramid. The Si(2)-O(5) bond length is 1.58 Å. The Si(2)-O(6) bond length is 1.74 Å. The Si(2)-O(7) bond length is 1.64 Å. The Si(2)-O(8) bond length is 1.59 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(4), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(3), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(4), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(2), one Cd(3), and one Si(1) atom. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to one Cd(2), one Cd(3), one Cd(4), and one Si(2) atom. In the sixth O site, O(6) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(3), one Cd(4), and one Si(2) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one Cd(1), one Cd(3), one Cd(4), and one Si(2) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one Cd(2), one Cd(3), one Cd(4), and one Si(2) atom.