FeOOH crystallizes in the orthorhombic Pnma space group. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 56°. H(1) is bonded in a single-bond 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 tetrahedra.
FeOOH crystallizes in the orthorhombic Pnma space group. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 56°. There is one shorter (2.09 Å) and two longer (2.11 Å) Fe(1)-O(1) bond lengths. There are two shorter (1.97 Å) and one longer (1.98 Å) Fe(1)-O(2) bond length. H(1) is bonded in a single-bond geometry to one O(1) and one O(2) atom. The H(1)-O(1) bond length is 0.99 Å. The H(1)-O(2) bond length is 1.71 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 tetrahedra.