Ca2SiO4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) 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 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one Si(1) atom.
Ca2SiO4 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. There is one shorter (2.48 Å) and one longer (2.67 Å) Ca(1)-O(1) bond length. There is one shorter (2.41 Å) and one longer (2.68 Å) Ca(1)-O(2) bond length. There is one shorter (2.41 Å) and one longer (2.42 Å) Ca(1)-O(3) bond length. There is one shorter (2.43 Å) and one longer (2.72 Å) Ca(1)-O(4) bond length. In the second Ca site, Ca(2) is bonded in a 7-coordinate geometry to one O(4), two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. The Ca(2)-O(4) bond length is 2.24 Å. There is one shorter (2.36 Å) and one longer (2.66 Å) Ca(2)-O(1) bond length. There is one shorter (2.43 Å) and one longer (2.58 Å) Ca(2)-O(2) bond length. There is one shorter (2.48 Å) and one longer (2.94 Å) Ca(2)-O(3) 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 1.66 Å. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(3) bond length is 1.65 Å. The Si(1)-O(4) bond length is 1.62 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1), two equivalent Ca(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Ca(2), two equivalent Ca(1), and one Si(1) atom.