NaCaHSiO4 crystallizes in the monoclinic P2_1 space group. Na(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. Ca(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) 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), one O(3), and one O(4) atom to form SiO4 tetrahedra that share corners with six equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-55°. H(1) is bonded in a distorted linear geometry to 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 Na(1), two equivalent Ca(1), and one Si(1) atom. In the second O site, O(2) is bonded to one Na(1), two equivalent Ca(1), and one Si(1) atom to form distorted corner-sharing ONaCa2Si tetrahedra. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Ca(1), one Si(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Ca(1), one Si(1), and one H(1) atom.
NaCaHSiO4 crystallizes in the monoclinic P2_1 space group. Na(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. The Na(1)-O(2) bond length is 2.27 Å. The Na(1)-O(3) bond length is 2.29 Å. The Na(1)-O(4) bond length is 2.34 Å. There is one shorter (2.56 Å) and one longer (2.90 Å) Na(1)-O(1) bond length. Ca(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form CaO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and edges with two equivalent Ca(1)O6 octahedra. The Ca(1)-O(3) bond length is 2.32 Å. The Ca(1)-O(4) bond length is 2.44 Å. There is one shorter (2.37 Å) and one longer (2.38 Å) Ca(1)-O(1) bond length. There is one shorter (2.34 Å) and one longer (2.35 Å) Ca(1)-O(2) bond length. 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 six equivalent Ca(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-55°. The Si(1)-O(1) bond length is 1.62 Å. The Si(1)-O(2) bond length is 1.62 Å. The Si(1)-O(3) bond length is 1.63 Å. The Si(1)-O(4) bond length is 1.69 Å. H(1) is bonded in a distorted linear geometry to one O(3) and one O(4) atom. The H(1)-O(3) bond length is 1.49 Å. The H(1)-O(4) bond length is 1.04 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Na(1), two equivalent Ca(1), and one Si(1) atom. In the second O site, O(2) is bonded to one Na(1), two equivalent Ca(1), and one Si(1) atom to form distorted corner-sharing ONaCa2Si tetrahedra. In the third O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Na(1), one Ca(1), one Si(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Na(1), one Ca(1), one Si(1), and one H(1) atom.