DOI: 10.17188/1741620
title: Materials Data on K2CaMg5Si8(HO12)2 by Materials Project

description: K2CaMg5Si8(HO12)2 is Esseneite-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 2-coordinate geometry to one H1+ and ten O2- atoms. The K–H bond length is 2.94 Å. There are a spread of K–O bond distances ranging from 2.70–3.27 Å. In the second K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.63–2.87 Å. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.39–2.83 Å. There are five inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- 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 2.07–2.13 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- 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 third Mg2+ site, Mg2+ is bonded to six O2- atoms to form distorted 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 2.04–2.24 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- 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 2.07–2.17 Å. In the fifth Mg2+ site, Mg2+ is bonded to six O2- 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 2.07–2.12 Å. There are eight inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- 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 33–55°. There is two shorter (1.61 Å) and two longer (1.71 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- 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 30–58°. There are a spread of Si–O bond distances ranging from 1.59–1.70 Å. In the third Si4+ site, Si4+ is bonded to four O2- 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 30–58°. There are a spread of Si–O bond distances ranging from 1.59–1.71 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- 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 33–55°. There are a spread of Si–O bond distances ranging from 1.61–1.72 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- 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 1.61–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- 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 59–61°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the seventh Si4+ site, Si4+ is bonded to four O2- 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 59–61°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the eighth Si4+ site, Si4+ is bonded to four O2- 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 1.61–1.66 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one K1+ and one O2- atom. The H–O bond length is 0.97 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Mg2+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ca2+, and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ca2+, and two Si4+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, two Mg2+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, two Mg2+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a 4-coordinate geometry to one K1+, two Mg2+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ca2+, and two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Si4+ atoms. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to two K1+ and two Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Ca2+, and two Si4+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Mg2+ and one H1+ atom. In the twentieth O2- site, O2- is bonded in a distorted single-bond geometry to three Mg2+ and one H1+ atom. In the twenty-first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Mg2+, and one Si4+ atom. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, one Mg2+, and one Si4+ atom. In the twenty-third O2- site, O2- is bonded in a 3-coordinate geometry to one K1+, one Mg2+, and one Si4+ atom. In the twenty-fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Mg2+, and one Si4+ atom.