FeOOH crystallizes in the monoclinic P2_1 space group. Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 22°. H(1) is bonded in a distorted linear geometry to two equivalent O(2) atoms. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OFe4 trigonal pyramids. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Fe(1) and two equivalent H(1) atoms.
FeOOH crystallizes in the monoclinic P2_1 space group. Fe(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form a mixture of edge and corner-sharing FeO6 octahedra. The corner-sharing octahedral tilt angles are 22°. There is one shorter (2.01 Å) and one longer (2.02 Å) Fe(1)-O(2) bond length. There are a spread of Fe(1)-O(1) bond distances ranging from 1.99-2.08 Å. H(1) is bonded in a distorted linear geometry to two equivalent O(2) atoms. There is one shorter (1.00 Å) and one longer (1.62 Å) H(1)-O(2) bond length. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Fe(1) atoms to form a mixture of edge and corner-sharing OFe4 trigonal pyramids. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Fe(1) and two equivalent H(1) atoms.