FeOOH crystallizes in the orthorhombic Pmn2_1 space group. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. H(1) is bonded in a distorted linear geometry to one O(1) and one O(2) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent Fe(1) and one H(1) atom. In the second O site, O(2) is bonded to three equivalent Fe(1) and one H(1) atom to form distorted corner-sharing OFe3H trigonal pyramids.
FeOOH crystallizes in the orthorhombic Pmn2_1 space group. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form a mixture of corner and edge-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles range from 52-54°. There are two shorter (2.11 Å) and one longer (2.18 Å) Fe(1)-O(1) bond length. All Fe(1)-O(2) bond lengths are 2.00 Å. H(1) is bonded in a distorted linear geometry to one O(1) and one O(2) atom. The H(1)-O(1) bond length is 1.02 Å. The H(1)-O(2) bond length is 1.61 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to three equivalent Fe(1) and one H(1) atom. In the second O site, O(2) is bonded to three equivalent Fe(1) and one H(1) atom to form distorted corner-sharing OFe3H trigonal pyramids.