DOI: 10.17188/1750530
title: Materials Data on KAl3Fe2Si2(HO6)2 by Materials Project

description: KFe2Al3Si2(HO6)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. K1+ is bonded to six O2- atoms to form KO6 octahedra that share corners with six AlO4 tetrahedra and corners with six SiO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.88–3.02 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two AlO4 tetrahedra, corners with two SiO4 tetrahedra, edges with three equivalent FeO6 octahedra, and edges with three equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.11–2.25 Å. In the second Fe2+ site, Fe2+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with two AlO4 tetrahedra, corners with two SiO4 tetrahedra, edges with three equivalent FeO6 octahedra, and edges with three equivalent AlO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.14–2.20 Å. There are three inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with two AlO4 tetrahedra, corners with two SiO4 tetrahedra, and edges with six FeO6 octahedra. There are a spread of Al–O bond distances ranging from 1.90–1.96 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two FeO6 octahedra, corners with three equivalent KO6 octahedra, and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–72°. There is three shorter (1.76 Å) and one longer (1.78 Å) Al–O bond length. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two FeO6 octahedra, corners with three equivalent KO6 octahedra, and corners with three equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–72°. There is three shorter (1.76 Å) and one longer (1.79 Å) Al–O bond length. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two FeO6 octahedra, corners with three equivalent KO6 octahedra, and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–68°. There are a spread of Si–O bond distances ranging from 1.63–1.69 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one AlO6 octahedra, corners with two FeO6 octahedra, corners with three equivalent KO6 octahedra, and corners with three equivalent AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 51–69°. There are a spread of Si–O bond distances ranging from 1.63–1.69 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 O2- atom. The H–O bond length is 0.97 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Fe2+, one Al3+, and one H1+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Fe2+, one Al3+, and one H1+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Al3+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+, one Al3+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Fe2+ and two Al3+ atoms. In the eighth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Fe2+, one Al3+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted tetrahedral geometry to two Fe2+ and two Al3+ atoms. In the tenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to two Fe2+, one Al3+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one Al3+, and one Si4+ atom.