DOI: 10.17188/1751485
title: Materials Data on Na3Mg5Si8(HO12)2 by Materials Project

description: Na3Mg5Si8(HO12)2 is Esseneite-derived structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Na sites. In the first Na site, Na is bonded in a 2-coordinate geometry to one H and eight O atoms. The Na–H bond length is 2.74 Å. There are a spread of Na–O bond distances ranging from 2.45–2.91 Å. In the second Na site, Na is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Na–O bond distances ranging from 2.35–2.87 Å. There are three inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with five MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.08–2.12 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six SiO4 tetrahedra and edges with three MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.20 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with four SiO4 tetrahedra and edges with six MgO6 octahedra. There are a spread of Mg–O bond distances ranging from 2.06–2.12 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–60°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 32–56°. There are a spread of Si–O bond distances ranging from 1.61–1.70 Å. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 27–57°. There are a spread of Si–O bond distances ranging from 1.61–1.69 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with three MgO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–60°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are two inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.97 Å. In the second H site, H is bonded in a single-bond geometry to one Na and one O atom. The H–O bond length is 0.96 Å. There are fourteen inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to two Na and two Si atoms. In the second O site, O is bonded in a 2-coordinate geometry to one Na and two Si atoms. In the third O site, O is bonded in a distorted trigonal non-coplanar geometry to one Na and two equivalent Si atoms. In the fourth O site, O is bonded in a 2-coordinate geometry to two Na and two Si atoms. In the fifth O site, O is bonded in a distorted single-bond geometry to three Mg and one H atom. In the sixth O site, O is bonded in a distorted rectangular see-saw-like geometry to one Na, two Mg, and one Si atom. In the seventh O site, O is bonded in a distorted single-bond geometry to three Mg and one H atom. In the eighth O site, O is bonded to three Mg and one Si atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. In the ninth O site, O is bonded in a 3-coordinate geometry to one Na and two equivalent Si atoms. In the tenth O site, O is bonded to three Mg and one Si atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. In the eleventh O site, O is bonded in a 3-coordinate geometry to one Na and two Si atoms. In the twelfth O site, O is bonded in a distorted T-shaped geometry to one Na, one Mg, and one Si atom. In the thirteenth O site, O is bonded in a distorted T-shaped geometry to one Na, one Mg, and one Si atom. In the fourteenth O site, O is bonded in a distorted rectangular see-saw-like geometry to one Na, two Mg, and one Si atom.