Materials Data on NaCaSiHO4 by Materials Project

Abstract

NaCaHSiO4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. Na1+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Na–O bond distances ranging from 2.30–2.92 Å. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six equivalent SiO4 tetrahedra and edges with two equivalent CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.33–2.47 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six equivalent CaO6 octahedra. The corner-sharing octahedra tilt angles range from 42–54°. There are a spread of Si–O bond distances ranging from 1.63–1.71 Å. H1+ is bonded in a linear geometry to two O2- atoms. There is one shorter (1.05 Å) and one longer (1.49 Å) H–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to two equivalent Na1+, two equivalent Ca2+, and one Si4+ atom. In the second O2- site, O2- is bonded to one Na1+, two equivalent Ca2+, and one Si4+ atom to form distorted corner-sharing ONaCa2Si tetrahedra. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+, one Ca2+, one Si4+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ca2+, one Si4+, and one H1+ atom.