The structure described by Sr2(FeO2)3 crystallizes in the tetragonal P4_2/mnm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and four equivalent O(4) atoms. 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 FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedra are not tilted. In the second Fe site, Fe(2) is bonded to one O(4) and three equivalent O(5) atoms to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with four equivalent Fe(2)O4 tetrahedra, and  an edgeedge with one Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a rectangular see-saw-like geometry to one Sr(1) and three equivalent Fe(2) atoms. In the second O site, O(1) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(2) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form a mixture of edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fourth O site, O(3) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form a mixture of edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(4) is bonded in a 6-coordinate geometry to four equivalent Sr(1), one Fe(1), and one Fe(2) atom. is represented by the CIF card [CIF]
data_Sr2(FeO2)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.642
_cell_length_b   5.642
_cell_length_c   19.433
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   618.569
_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
  Sr  Sr0  1  0.738  0.738  0.412  1.0
  Sr  Sr1  1  0.262  0.262  0.412  1.0
  Sr  Sr2  1  0.762  0.238  0.912  1.0
  Sr  Sr3  1  0.238  0.762  0.912  1.0
  Sr  Sr4  1  0.262  0.262  0.588  1.0
  Sr  Sr5  1  0.738  0.738  0.588  1.0
  Sr  Sr6  1  0.238  0.762  0.088  1.0
  Sr  Sr7  1  0.762  0.238  0.088  1.0
  Fe  Fe8  1  0.246  0.754  0.500  1.0
  Fe  Fe9  1  0.754  0.246  0.500  1.0
  Fe  Fe10  1  0.254  0.254  0.000  1.0
  Fe  Fe11  1  0.746  0.746  0.000  1.0
  Fe  Fe12  1  0.176  0.824  0.295  1.0
  Fe  Fe13  1  0.824  0.176  0.295  1.0
  Fe  Fe14  1  0.324  0.324  0.795  1.0
  Fe  Fe15  1  0.676  0.676  0.795  1.0
  Fe  Fe16  1  0.824  0.176  0.705  1.0
  Fe  Fe17  1  0.176  0.824  0.705  1.0
  Fe  Fe18  1  0.676  0.676  0.205  1.0
  Fe  Fe19  1  0.324  0.324  0.205  1.0
  O  O20  1  0.000  0.000  0.500  1.0
  O  O21  1  0.500  0.500  0.000  1.0
  O  O22  1  0.000  0.500  0.500  1.0
  O  O23  1  0.500  0.000  0.000  1.0
  O  O24  1  0.500  0.000  0.500  1.0
  O  O25  1  0.000  0.500  0.000  1.0
  O  O26  1  0.500  0.500  0.500  1.0
  O  O27  1  0.000  0.000  0.000  1.0
  O  O28  1  0.256  0.744  0.387  1.0
  O  O29  1  0.744  0.256  0.387  1.0
  O  O30  1  0.244  0.244  0.887  1.0
  O  O31  1  0.756  0.756  0.887  1.0
  O  O32  1  0.744  0.256  0.613  1.0
  O  O33  1  0.256  0.744  0.613  1.0
  O  O34  1  0.756  0.756  0.113  1.0
  O  O35  1  0.244  0.244  0.113  1.0
  O  O36  1  0.819  0.819  0.286  1.0
  O  O37  1  0.181  0.181  0.286  1.0
  O  O38  1  0.681  0.319  0.786  1.0
  O  O39  1  0.319  0.681  0.786  1.0
  O  O40  1  0.181  0.181  0.714  1.0
  O  O41  1  0.819  0.819  0.714  1.0
  O  O42  1  0.319  0.681  0.214  1.0
  O  O43  1  0.681  0.319  0.214  1.0
[/CIF]
.
The structure described by Sr2(FeO2)3 crystallizes in the tetragonal P4_2/mnm space group. Sr(1) is bonded in a 9-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and four equivalent O(4) atoms. 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 FeO6 octahedra that share corners with four equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O4 tetrahedra. The corner-sharing octahedra are not tilted. In the second Fe site, Fe(2) is bonded to one O(4) and three equivalent O(5) atoms to form FeO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra, corners with four equivalent Fe(2)O4 tetrahedra, and  an edgeedge with one Fe(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a rectangular see-saw-like geometry to one Sr(1) and three equivalent Fe(2) atoms. In the second O site, O(1) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form a mixture of distorted edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the third O site, O(2) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form a mixture of edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedral tilt angles are 2°. In the fourth O site, O(3) is bonded to four equivalent Sr(1) and two equivalent Fe(1) atoms to form a mixture of edge, face, and corner-sharing OSr4Fe2 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(4) is bonded in a 6-coordinate geometry to four equivalent Sr(1), one Fe(1), and one Fe(2) atom. is represented by the CIF card [CIF]
data_Sr2(FeO2)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.642
_cell_length_b   5.642
_cell_length_c   19.433
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   618.569
_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
  Sr  Sr0  1  0.738  0.738  0.412  1.0
  Sr  Sr1  1  0.262  0.262  0.412  1.0
  Sr  Sr2  1  0.762  0.238  0.912  1.0
  Sr  Sr3  1  0.238  0.762  0.912  1.0
  Sr  Sr4  1  0.262  0.262  0.588  1.0
  Sr  Sr5  1  0.738  0.738  0.588  1.0
  Sr  Sr6  1  0.238  0.762  0.088  1.0
  Sr  Sr7  1  0.762  0.238  0.088  1.0
  Fe  Fe8  1  0.246  0.754  0.500  1.0
  Fe  Fe9  1  0.754  0.246  0.500  1.0
  Fe  Fe10  1  0.254  0.254  0.000  1.0
  Fe  Fe11  1  0.746  0.746  0.000  1.0
  Fe  Fe12  1  0.176  0.824  0.295  1.0
  Fe  Fe13  1  0.824  0.176  0.295  1.0
  Fe  Fe14  1  0.324  0.324  0.795  1.0
  Fe  Fe15  1  0.676  0.676  0.795  1.0
  Fe  Fe16  1  0.824  0.176  0.705  1.0
  Fe  Fe17  1  0.176  0.824  0.705  1.0
  Fe  Fe18  1  0.676  0.676  0.205  1.0
  Fe  Fe19  1  0.324  0.324  0.205  1.0
  O  O20  1  0.000  0.000  0.500  1.0
  O  O21  1  0.500  0.500  0.000  1.0
  O  O22  1  0.000  0.500  0.500  1.0
  O  O23  1  0.500  0.000  0.000  1.0
  O  O24  1  0.500  0.000  0.500  1.0
  O  O25  1  0.000  0.500  0.000  1.0
  O  O26  1  0.500  0.500  0.500  1.0
  O  O27  1  0.000  0.000  0.000  1.0
  O  O28  1  0.256  0.744  0.387  1.0
  O  O29  1  0.744  0.256  0.387  1.0
  O  O30  1  0.244  0.244  0.887  1.0
  O  O31  1  0.756  0.756  0.887  1.0
  O  O32  1  0.744  0.256  0.613  1.0
  O  O33  1  0.256  0.744  0.613  1.0
  O  O34  1  0.756  0.756  0.113  1.0
  O  O35  1  0.244  0.244  0.113  1.0
  O  O36  1  0.819  0.819  0.286  1.0
  O  O37  1  0.181  0.181  0.286  1.0
  O  O38  1  0.681  0.319  0.786  1.0
  O  O39  1  0.319  0.681  0.786  1.0
  O  O40  1  0.181  0.181  0.714  1.0
  O  O41  1  0.819  0.819  0.714  1.0
  O  O42  1  0.319  0.681  0.214  1.0
  O  O43  1  0.681  0.319  0.214  1.0
[/CIF]
.