Materials Data on NaCa2Si3HO9 by Materials Project

Abstract

NaCa2Si3O8(OH) is Esseneite-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na1+ is bonded in a 4-coordinate geometry to one H1+ and eight O2- atoms. The Na–H bond length is 2.34 Å. There are a spread of Na–O bond distances ranging from 2.32–3.09 Å. There are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six SiO4 tetrahedra and edges with four CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.34–2.46 Å. In the second Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six SiO4 tetrahedra and edges with four CaO6 octahedra. There are a spread of Ca–O bond distances ranging from 2.34–2.46 Å. There are three inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–59°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–66°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four CaO6 octahedra and corners with two SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–66°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. H1+ is bonded in a distorted linear geometry to one Na1+ and two O2- atoms. There is one shorter (1.07 Å) and one longer (1.44 Å) H–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Na1+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a distorted T-shaped geometry to one Na1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded to three Ca2+ and one Si4+ atom to form distorted edge-sharing OCa3Si tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ca2+, one Si4+, and one H1+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two Ca2+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+, two Ca2+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one Ca2+, one Si4+, and one H1+ atom.