Materials Data on FeHO2 by Materials Project

Abstract

FeOOH crystallizes in the orthorhombic Cmc2_1 space group. The structure is two-dimensional and consists of two FeOOH sheets oriented in the (0, 1, 0) direction. Fe3+ is bonded to one H1+ and six O2- atoms to form a mixture of distorted edge and corner-sharing FeHO6 pentagonal bipyramids. The Fe–H bond length is 1.99 Å. There are a spread of Fe–O bond distances ranging from 1.99–2.07 Å. H1+ is bonded in a bent 150 degrees geometry to one Fe3+ and two equivalent O2- atoms. Both H–O bond lengths are 1.37 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Fe3+ atoms to form a mixture of distorted edge and corner-sharing OFe4 trigonal pyramids. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Fe3+ and two equivalent H1+ atoms.