The material structure described by Fe(SO4)2 crystallizes in the trigonal R3 space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and corners with three equivalent S(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and corners with three equivalent S(2)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to three equivalent O(3) and three equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and corners with three equivalent S(2)O4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(2), one O(3), one O(4), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-41°. In the second S site, S(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form SO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-39°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(1) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(3) and one S(2) atom. In the third O site, O(6) is bonded in a single-bond geometry to one S(2) atom. In the fourth O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(2) and one S(2) atom. In the fifth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(2) and one S(1) atom. In the sixth O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(2) atom. In the seventh O site, O(2) is bonded in a single-bond geometry to one S(1) atom. In the eighth O site, O(3) is bonded in a bent 150 degrees geometry to one Fe(3) and one S(1) atom. is represented by the CIF file [CIF]
data_Fe(SO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.967
_cell_length_b   8.967
_cell_length_c   8.967
_cell_angle_alpha   56.213
_cell_angle_beta   56.213
_cell_angle_gamma   56.213
_symmetry_Int_Tables_number   1
_cell_volume   465.185
_cell_formula_units_Z   3
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  0.356  0.356  0.356  1.0
  Fe  Fe1  1  0.643  0.643  0.643  1.0
  Fe  Fe2  1  0.851  0.851  0.851  1.0
  S  S3  1  0.467  0.744  0.039  1.0
  S  S4  1  0.744  0.039  0.467  1.0
  S  S5  1  0.039  0.467  0.744  1.0
  S  S6  1  0.960  0.539  0.249  1.0
  S  S7  1  0.249  0.960  0.539  1.0
  S  S8  1  0.539  0.249  0.960  1.0
  O  O9  1  0.513  0.291  0.114  1.0
  O  O10  1  0.114  0.513  0.291  1.0
  O  O11  1  0.339  0.943  0.005  1.0
  O  O12  1  0.291  0.114  0.513  1.0
  O  O13  1  0.655  0.719  0.024  1.0
  O  O14  1  0.388  0.611  0.232  1.0
  O  O15  1  0.611  0.232  0.388  1.0
  O  O16  1  0.943  0.005  0.339  1.0
  O  O17  1  0.232  0.388  0.611  1.0
  O  O18  1  0.981  0.679  0.048  1.0
  O  O19  1  0.971  0.359  0.274  1.0
  O  O20  1  0.274  0.971  0.359  1.0
  O  O21  1  0.719  0.024  0.655  1.0
  O  O22  1  0.024  0.655  0.719  1.0
  O  O23  1  0.005  0.339  0.943  1.0
  O  O24  1  0.769  0.629  0.381  1.0
  O  O25  1  0.048  0.981  0.679  1.0
  O  O26  1  0.381  0.769  0.629  1.0
  O  O27  1  0.629  0.381  0.769  1.0
  O  O28  1  0.359  0.274  0.971  1.0
  O  O29  1  0.680  0.894  0.505  1.0
  O  O30  1  0.679  0.048  0.981  1.0
  O  O31  1  0.894  0.505  0.680  1.0
  O  O32  1  0.505  0.680  0.894  1.0
[/CIF]
.
The material structure described by Fe(SO4)2 crystallizes in the trigonal R3 space group. There are three inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to three equivalent O(1) and three equivalent O(4) atoms to form FeO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and corners with three equivalent S(2)O4 tetrahedra. In the second Fe site, Fe(2) is bonded to three equivalent O(7) and three equivalent O(8) atoms to form FeO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and corners with three equivalent S(2)O4 tetrahedra. In the third Fe site, Fe(3) is bonded to three equivalent O(3) and three equivalent O(5) atoms to form FeO6 octahedra that share corners with three equivalent S(1)O4 tetrahedra and corners with three equivalent S(2)O4 tetrahedra. There are two inequivalent S sites. In the first S site, S(1) is bonded to one O(2), one O(3), one O(4), and one O(8) atom to form SO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 25-41°. In the second S site, S(2) is bonded to one O(1), one O(5), one O(6), and one O(7) atom to form SO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra, and  a cornercorner with one Fe(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 26-39°. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(1) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one Fe(3) and one S(2) atom. In the third O site, O(6) is bonded in a single-bond geometry to one S(2) atom. In the fourth O site, O(7) is bonded in a bent 150 degrees geometry to one Fe(2) and one S(2) atom. In the fifth O site, O(8) is bonded in a bent 150 degrees geometry to one Fe(2) and one S(1) atom. In the sixth O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one S(2) atom. In the seventh O site, O(2) is bonded in a single-bond geometry to one S(1) atom. In the eighth O site, O(3) is bonded in a bent 150 degrees geometry to one Fe(3) and one S(1) atom. is represented by the CIF file [CIF]
data_Fe(SO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.967
_cell_length_b   8.967
_cell_length_c   8.967
_cell_angle_alpha   56.213
_cell_angle_beta   56.213
_cell_angle_gamma   56.213
_symmetry_Int_Tables_number   1
_cell_volume   465.185
_cell_formula_units_Z   3
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  0.356  0.356  0.356  1.0
  Fe  Fe1  1  0.643  0.643  0.643  1.0
  Fe  Fe2  1  0.851  0.851  0.851  1.0
  S  S3  1  0.467  0.744  0.039  1.0
  S  S4  1  0.744  0.039  0.467  1.0
  S  S5  1  0.039  0.467  0.744  1.0
  S  S6  1  0.960  0.539  0.249  1.0
  S  S7  1  0.249  0.960  0.539  1.0
  S  S8  1  0.539  0.249  0.960  1.0
  O  O9  1  0.513  0.291  0.114  1.0
  O  O10  1  0.114  0.513  0.291  1.0
  O  O11  1  0.339  0.943  0.005  1.0
  O  O12  1  0.291  0.114  0.513  1.0
  O  O13  1  0.655  0.719  0.024  1.0
  O  O14  1  0.388  0.611  0.232  1.0
  O  O15  1  0.611  0.232  0.388  1.0
  O  O16  1  0.943  0.005  0.339  1.0
  O  O17  1  0.232  0.388  0.611  1.0
  O  O18  1  0.981  0.679  0.048  1.0
  O  O19  1  0.971  0.359  0.274  1.0
  O  O20  1  0.274  0.971  0.359  1.0
  O  O21  1  0.719  0.024  0.655  1.0
  O  O22  1  0.024  0.655  0.719  1.0
  O  O23  1  0.005  0.339  0.943  1.0
  O  O24  1  0.769  0.629  0.381  1.0
  O  O25  1  0.048  0.981  0.679  1.0
  O  O26  1  0.381  0.769  0.629  1.0
  O  O27  1  0.629  0.381  0.769  1.0
  O  O28  1  0.359  0.274  0.971  1.0
  O  O29  1  0.680  0.894  0.505  1.0
  O  O30  1  0.679  0.048  0.981  1.0
  O  O31  1  0.894  0.505  0.680  1.0
  O  O32  1  0.505  0.680  0.894  1.0
[/CIF]
.