The structure described by Rb2Mg(FeO2)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent O(1), and four equivalent O(2) atoms. Mg(1) is bonded to two equivalent Rb(2), two equivalent O(1), and two equivalent O(2) atoms to form MgRb2O4 tetrahedra that share corners with two equivalent Mg(1)Rb2O4 tetrahedra, corners with two equivalent Fe(1)Rb2O4 trigonal pyramids, corners with four equivalent Fe(2)Rb2O4 trigonal pyramids, edges with two equivalent Fe(2)Rb2O4 trigonal pyramids, and edges with three equivalent Fe(1)Rb2O4 trigonal pyramids. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Rb(2), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeRb2O4 trigonal pyramids that share corners with two equivalent Mg(1)Rb2O4 tetrahedra, corners with two equivalent Fe(1)Rb2O4 trigonal pyramids, corners with two equivalent Fe(2)Rb2O4 trigonal pyramids, edges with three equivalent Mg(1)Rb2O4 tetrahedra, and faces with two equivalent Fe(2)Rb2O4 trigonal pyramids. In the second Fe site, Fe(2) is bonded to two equivalent Rb(2), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeRb2O4 trigonal pyramids that share corners with four equivalent Mg(1)Rb2O4 tetrahedra, corners with two equivalent Fe(1)Rb2O4 trigonal pyramids, corners with two equivalent Fe(2)Rb2O4 trigonal pyramids, edges with two equivalent Mg(1)Rb2O4 tetrahedra, and faces with two equivalent Fe(1)Rb2O4 trigonal pyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Rb(2), two equivalent Rb(1), one Mg(1), one Fe(1), and one Fe(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Mg(1), one Fe(1), and one Fe(2) atom. is represented by the CIF file [CIF]
data_Rb2Mg(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.856
_cell_length_b   5.856
_cell_length_c   5.795
_cell_angle_alpha   71.728
_cell_angle_beta   108.272
_cell_angle_gamma   68.568
_symmetry_Int_Tables_number   1
_cell_volume   153.686
_cell_formula_units_Z   1
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
  Rb  Rb0  1  0.353  0.353  0.750  1.0
  Rb  Rb1  1  0.613  0.613  0.250  1.0
  Mg  Mg2  1  0.731  0.731  0.750  1.0
  Fe  Fe3  1  0.011  0.011  0.750  1.0
  Fe  Fe4  1  0.007  0.007  0.250  1.0
  O  O5  1  0.317  0.906  0.632  1.0
  O  O6  1  0.960  0.779  0.054  1.0
  O  O7  1  0.906  0.317  0.868  1.0
  O  O8  1  0.779  0.960  0.446  1.0
[/CIF]
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The structure described by Rb2Mg(FeO2)2 crystallizes in the monoclinic C2 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 12-coordinate geometry to two equivalent Mg(1), two equivalent Fe(1), two equivalent Fe(2), two equivalent O(1), and four equivalent O(2) atoms. Mg(1) is bonded to two equivalent Rb(2), two equivalent O(1), and two equivalent O(2) atoms to form MgRb2O4 tetrahedra that share corners with two equivalent Mg(1)Rb2O4 tetrahedra, corners with two equivalent Fe(1)Rb2O4 trigonal pyramids, corners with four equivalent Fe(2)Rb2O4 trigonal pyramids, edges with two equivalent Fe(2)Rb2O4 trigonal pyramids, and edges with three equivalent Fe(1)Rb2O4 trigonal pyramids. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent Rb(2), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeRb2O4 trigonal pyramids that share corners with two equivalent Mg(1)Rb2O4 tetrahedra, corners with two equivalent Fe(1)Rb2O4 trigonal pyramids, corners with two equivalent Fe(2)Rb2O4 trigonal pyramids, edges with three equivalent Mg(1)Rb2O4 tetrahedra, and faces with two equivalent Fe(2)Rb2O4 trigonal pyramids. In the second Fe site, Fe(2) is bonded to two equivalent Rb(2), two equivalent O(1), and two equivalent O(2) atoms to form distorted FeRb2O4 trigonal pyramids that share corners with four equivalent Mg(1)Rb2O4 tetrahedra, corners with two equivalent Fe(1)Rb2O4 trigonal pyramids, corners with two equivalent Fe(2)Rb2O4 trigonal pyramids, edges with two equivalent Mg(1)Rb2O4 tetrahedra, and faces with two equivalent Fe(1)Rb2O4 trigonal pyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one Rb(2), two equivalent Rb(1), one Mg(1), one Fe(1), and one Fe(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Mg(1), one Fe(1), and one Fe(2) atom. is represented by the CIF file [CIF]
data_Rb2Mg(FeO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.856
_cell_length_b   5.856
_cell_length_c   5.795
_cell_angle_alpha   71.728
_cell_angle_beta   108.272
_cell_angle_gamma   68.568
_symmetry_Int_Tables_number   1
_cell_volume   153.686
_cell_formula_units_Z   1
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
  Rb  Rb0  1  0.353  0.353  0.750  1.0
  Rb  Rb1  1  0.613  0.613  0.250  1.0
  Mg  Mg2  1  0.731  0.731  0.750  1.0
  Fe  Fe3  1  0.011  0.011  0.750  1.0
  Fe  Fe4  1  0.007  0.007  0.250  1.0
  O  O5  1  0.317  0.906  0.632  1.0
  O  O6  1  0.960  0.779  0.054  1.0
  O  O7  1  0.906  0.317  0.868  1.0
  O  O8  1  0.779  0.960  0.446  1.0
[/CIF]
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