DOI: 10.17188/1663935
title: Materials Data on Fe7Si3(H4O9)2 by Materials Project

description: Fe7Si3(H4O9)2 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Fe7Si3(H4O9)2 sheet oriented in the (0, 1, 1) direction. there are seven inequivalent Fe+2.29+ sites. In the first Fe+2.29+ site, Fe+2.29+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with three FeO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–64°. There is three shorter (1.89 Å) and one longer (1.92 Å) Fe–O bond length. In the second Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one FeO4 tetrahedra, a cornercorner with one SiO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.08–2.29 Å. In the third Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two SiO4 tetrahedra and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.07–2.23 Å. In the fourth Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two SiO4 tetrahedra and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.10–2.25 Å. In the fifth Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one FeO4 tetrahedra, a cornercorner with one SiO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.06–2.23 Å. In the sixth Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form FeO6 octahedra that share a cornercorner with one FeO4 tetrahedra, a cornercorner with one SiO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.11 Å. In the seventh Fe+2.29+ site, Fe+2.29+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two SiO4 tetrahedra and edges with six FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.09–2.21 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 three FeO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 55–59°. There are a spread of Si–O bond distances ranging from 1.61–1.68 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three FeO6 octahedra, a cornercorner with one SiO4 tetrahedra, and corners with two equivalent FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–60°. There are a spread of Si–O bond distances ranging from 1.63–1.68 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three FeO6 octahedra, a cornercorner with one FeO4 tetrahedra, and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 56–57°. There is two shorter (1.63 Å) and two longer (1.70 Å) Si–O bond length. There are eight 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 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the seventh 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 eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.29+ and one Si4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe+2.29+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe+2.29+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted tetrahedral geometry to four Fe+2.29+ atoms. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe+2.29+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe+2.29+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Fe+2.29+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom. In the thirteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom. In the seventeenth O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom. In the eighteenth O2- site, O2- is bonded in a distorted single-bond geometry to three Fe+2.29+ and one H1+ atom.