Co(SiO3)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form distorted CoO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with two equivalent Co(2)O6 octahedra. In the second Co site, Co(2) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and edges with two equivalent Co(1)O6 octahedra. 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  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-60°. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-63°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Co(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Co(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(2), and one Si(2) atom.
Co(SiO3)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(6) atoms to form distorted CoO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, and edges with two equivalent Co(2)O6 octahedra. Both Co(1)-O(2) bond lengths are 1.82 Å. Both Co(1)-O(3) bond lengths are 2.08 Å. Both Co(1)-O(6) bond lengths are 2.02 Å. In the second Co site, Co(2) is bonded to two equivalent O(3), two equivalent O(5), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, corners with four equivalent Si(2)O4 tetrahedra, and edges with two equivalent Co(1)O6 octahedra. Both Co(2)-O(3) bond lengths are 1.90 Å. Both Co(2)-O(5) bond lengths are 1.85 Å. Both Co(2)-O(6) bond lengths are 1.98 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  a cornercorner with one Co(2)O6 octahedra, corners with two equivalent Co(1)O6 octahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-60°. The Si(1)-O(1) bond length is 1.62 Å. The Si(1)-O(2) bond length is 1.63 Å. The Si(1)-O(3) bond length is 1.67 Å. The Si(1)-O(4) bond length is 1.62 Å. In the second Si site, Si(2) is bonded to one O(1), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share  a cornercorner with one Co(1)O6 octahedra, corners with two equivalent Co(2)O6 octahedra, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 34-63°. The Si(2)-O(1) bond length is 1.63 Å. The Si(2)-O(4) bond length is 1.62 Å. The Si(2)-O(5) bond length is 1.63 Å. The Si(2)-O(6) bond length is 1.68 Å. There are six inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Co(1) and one Si(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one Si(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Co(2) and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Co(1), one Co(2), and one Si(2) atom.