The material described by FeOOH crystallizes in the monoclinic P2_1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted edge-sharing FeO6 octahedra. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Fe(1), two equivalent Fe(2), and one H(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Fe(2), two equivalent Fe(1), and one H(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_FeHO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.741
_cell_length_b   3.055
_cell_length_c   4.963
_cell_angle_alpha   88.831
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   147.669
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Fe  Fe0  1  0.620  0.012  0.297  1.0
  Fe  Fe1  1  0.120  0.988  0.703  1.0
  Fe  Fe2  1  0.315  0.494  0.191  1.0
  Fe  Fe3  1  0.815  0.506  0.809  1.0
  H  H4  1  0.374  0.988  0.715  1.0
  H  H5  1  0.874  0.012  0.285  1.0
  H  H6  1  0.548  0.535  0.850  1.0
  H  H7  1  0.048  0.465  0.150  1.0
  O  O8  1  0.319  0.987  0.885  1.0
  O  O9  1  0.819  0.013  0.115  1.0
  O  O10  1  0.671  0.503  0.529  1.0
  O  O11  1  0.171  0.497  0.471  1.0
  O  O12  1  0.415  0.995  0.368  1.0
  O  O13  1  0.915  0.005  0.632  1.0
  O  O14  1  0.599  0.523  0.020  1.0
  O  O15  1  0.099  0.477  0.980  1.0
[/CIF]
.
The material described by FeOOH crystallizes in the monoclinic P2_1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form distorted edge-sharing FeO6 octahedra. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Fe(1), two equivalent Fe(2), and one H(1) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Fe(2) and two equivalent Fe(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Fe(1) and two equivalent Fe(2) atoms. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one Fe(2), two equivalent Fe(1), and one H(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_FeHO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.741
_cell_length_b   3.055
_cell_length_c   4.963
_cell_angle_alpha   88.831
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   147.669
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
loop_
 _atom_site_type_symbol
 _atom_site_label
 _atom_site_symmetry_multiplicity
 _atom_site_fract_x
 _atom_site_fract_y
 _atom_site_fract_z
 _atom_site_occupancy
  Fe  Fe0  1  0.620  0.012  0.297  1.0
  Fe  Fe1  1  0.120  0.988  0.703  1.0
  Fe  Fe2  1  0.315  0.494  0.191  1.0
  Fe  Fe3  1  0.815  0.506  0.809  1.0
  H  H4  1  0.374  0.988  0.715  1.0
  H  H5  1  0.874  0.012  0.285  1.0
  H  H6  1  0.548  0.535  0.850  1.0
  H  H7  1  0.048  0.465  0.150  1.0
  O  O8  1  0.319  0.987  0.885  1.0
  O  O9  1  0.819  0.013  0.115  1.0
  O  O10  1  0.671  0.503  0.529  1.0
  O  O11  1  0.171  0.497  0.471  1.0
  O  O12  1  0.415  0.995  0.368  1.0
  O  O13  1  0.915  0.005  0.632  1.0
  O  O14  1  0.599  0.523  0.020  1.0
  O  O15  1  0.099  0.477  0.980  1.0
[/CIF]
.