CaSiO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted CaO8 hexagonal bipyramids that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with two equivalent Si(2)O4 tetrahedra, edges with six equivalent Ca(2)O8 hexagonal bipyramids, edges with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Si(2)O4 tetrahedra. In the second Ca site, Ca(2) is bonded to one O(1), one O(3), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form distorted CaO8 hexagonal bipyramids that share  a cornercorner with one Ca(1)O8 hexagonal bipyramid,  a cornercorner with one Ca(2)O8 hexagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, edges with three equivalent Ca(1)O8 hexagonal bipyramids, edges with three equivalent Ca(2)O8 hexagonal bipyramids,  an edgeedge with one Si(1)O4 tetrahedra, and edges with three equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Ca(1)O8 hexagonal bipyramids, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O8 hexagonal bipyramid,  a cornercorner with one Ca(2)O8 hexagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Ca(1)O8 hexagonal bipyramid, and edges with three equivalent Ca(2)O8 hexagonal bipyramids. There are five inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(2) atom. In the second O site, O(5) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(2) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(2) and two equivalent Si(2) atoms. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Si(1), and one Si(2) atom.
CaSiO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to two equivalent O(2), two equivalent O(3), two equivalent O(4), and two equivalent O(5) atoms to form distorted CaO8 hexagonal bipyramids that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with two equivalent Si(2)O4 tetrahedra, edges with six equivalent Ca(2)O8 hexagonal bipyramids, edges with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Si(2)O4 tetrahedra. Both Ca(1)-O(2) bond lengths are 2.61 Å. Both Ca(1)-O(3) bond lengths are 2.62 Å. Both Ca(1)-O(4) bond lengths are 2.68 Å. Both Ca(1)-O(5) bond lengths are 2.32 Å. In the second Ca site, Ca(2) is bonded to one O(1), one O(3), two equivalent O(2), two equivalent O(4), and two equivalent O(5) atoms to form distorted CaO8 hexagonal bipyramids that share  a cornercorner with one Ca(1)O8 hexagonal bipyramid,  a cornercorner with one Ca(2)O8 hexagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra, edges with three equivalent Ca(1)O8 hexagonal bipyramids, edges with three equivalent Ca(2)O8 hexagonal bipyramids,  an edgeedge with one Si(1)O4 tetrahedra, and edges with three equivalent Si(2)O4 tetrahedra. The Ca(2)-O(1) bond length is 2.60 Å. The Ca(2)-O(3) bond length is 2.59 Å. There is one shorter (2.29 Å) and one longer (2.63 Å) Ca(2)-O(2) bond length. There is one shorter (2.29 Å) and one longer (2.63 Å) Ca(2)-O(4) bond length. There is one shorter (2.66 Å) and one longer (2.67 Å) Ca(2)-O(5) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(2) and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with two equivalent Si(2)O4 tetrahedra, edges with two equivalent Ca(1)O8 hexagonal bipyramids, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. Both Si(1)-O(2) bond lengths are 1.60 Å. Both Si(1)-O(3) bond lengths are 1.68 Å. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form SiO4 tetrahedra that share  a cornercorner with one Ca(1)O8 hexagonal bipyramid,  a cornercorner with one Ca(2)O8 hexagonal bipyramid,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Ca(1)O8 hexagonal bipyramid, and edges with three equivalent Ca(2)O8 hexagonal bipyramids. The Si(2)-O(1) bond length is 1.68 Å. The Si(2)-O(3) bond length is 1.68 Å. The Si(2)-O(4) bond length is 1.60 Å. The Si(2)-O(5) bond length is 1.61 Å. There are five inequivalent O sites. In the first O site, O(4) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(2) atom. In the second O site, O(5) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(2) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(2) and two equivalent Si(2) atoms. In the fourth O site, O(2) is bonded in a 4-coordinate geometry to one Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Si(1), and one Si(2) atom.