NaCaSiO4 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(3) atoms. Ca(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and edges with two equivalent Ca(1)O6 octahedra. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with six equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-57°. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Ca(1), and one Si(1) atom to form distorted corner-sharing ONaCa2Si tetrahedra. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Ca(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Ca(1), and one Si(1) atom.
NaCaSiO4 crystallizes in the monoclinic P2_1/m space group. Na(1) is bonded in a 5-coordinate geometry to one O(1), two equivalent O(2), and two equivalent O(3) atoms. The Na(1)-O(1) bond length is 2.34 Å. There is one shorter (2.60 Å) and one longer (2.81 Å) Na(1)-O(2) bond length. Both Na(1)-O(3) bond lengths are 2.32 Å. Ca(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form CaO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and edges with two equivalent Ca(1)O6 octahedra. Both Ca(1)-O(1) bond lengths are 2.34 Å. Both Ca(1)-O(2) bond lengths are 2.43 Å. Both Ca(1)-O(3) bond lengths are 2.37 Å. Si(1) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with six equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-57°. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(2) bond length is 1.64 Å. Both Si(1)-O(3) bond lengths are 1.66 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to one Na(1), two equivalent Ca(1), and one Si(1) atom to form distorted corner-sharing ONaCa2Si tetrahedra. In the second O site, O(2) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Ca(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Na(1), one Ca(1), and one Si(1) atom.