DOI: 10.17188/1651691
title: Materials Data on Fe21HO32 by Materials Project

description: Fe21HO32 crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are eight inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.98–2.15 Å. In the second Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 2.01–2.11 Å. In the third Fe3+ site, Fe3+ is bonded to six O2- atoms to form FeO6 octahedra that share corners with six FeO4 tetrahedra and edges with five FeO6 octahedra. There are a spread of Fe–O bond distances ranging from 1.97–2.12 Å. In the fourth Fe3+ site, Fe3+ is bonded to four O2- atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 52–59°. There are a spread of Fe–O bond distances ranging from 1.91–1.99 Å. In the fifth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with nine FeO6 octahedra and a cornercorner with one FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–64°. There is one shorter (1.79 Å) and three longer (2.00 Å) Fe–O bond length. In the sixth Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with nine FeO6 octahedra and a cornercorner with one FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–62°. There are a spread of Fe–O bond distances ranging from 1.79–2.01 Å. In the seventh Fe3+ site, Fe3+ is bonded to four O2- atoms to form corner-sharing FeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–56°. There is three shorter (1.94 Å) and one longer (1.95 Å) Fe–O bond length. In the eighth Fe3+ site, Fe3+ is bonded to four O2- atoms to form corner-sharing FeO4 tetrahedra. There is one shorter (1.86 Å) and three longer (1.89 Å) Fe–O bond length. H1+ is bonded in a trigonal non-coplanar geometry to three equivalent O2- atoms. All H–O bond lengths are 1.55 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the third O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to four Fe3+ atoms. In the fourth O2- site, O2- is bonded to four Fe3+ atoms to form distorted corner-sharing OFe4 trigonal pyramids. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Fe3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe3+ atoms. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Fe3+ and one H1+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Fe3+ atoms. In the ninth O2- site, O2- is bonded in a linear geometry to two Fe3+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to two Fe3+ atoms.