The compound described by Rb2MgFe4O7 crystallizes in the triclinic P1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(5), one O(6), one O(7), and two equivalent O(3) atoms. Mg(1) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form MgO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O5 trigonal bipyramids,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(1)O4 trigonal pyramid. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form distorted FeO4 trigonal pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(2)O4 tetrahedra,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Fe(3)O5 trigonal bipyramids, and  a cornercorner with one Fe(1)O4 trigonal pyramid. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(4), one O(5), and one O(6) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(1)O4 trigonal pyramid. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(5), one O(6), and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Rb(1), one Rb(2), one Mg(1), one Fe(1), and one Fe(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Rb(1), one Rb(2), one Fe(2), one Fe(3), and one Fe(4) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Mg(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Rb(1), one Mg(1), one Fe(1), one Fe(3), and one Fe(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Rb(1), one Rb(2), one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Fe(2), one Fe(3), and one Fe(4) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Mg(1), one Fe(1), and one Fe(4) atom. is represented by the CIF file [CIF]
data_Rb2MgFe4O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.526
_cell_length_b   5.522
_cell_length_c   7.471
_cell_angle_alpha   90.197
_cell_angle_beta   98.178
_cell_angle_gamma   112.650
_symmetry_Int_Tables_number   1
_cell_volume   207.802
_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  0.363  0.734  0.995  1.0
  Rb  Rb1  1  0.714  0.374  0.937  1.0
  Mg  Mg2  1  0.115  0.117  0.224  1.0
  Fe  Fe3  1  0.772  0.712  0.385  1.0
  Fe  Fe4  1  0.039  0.065  0.716  1.0
  Fe  Fe5  1  0.288  0.647  0.514  1.0
  Fe  Fe6  1  0.614  0.163  0.479  1.0
  O  O7  1  0.107  0.750  0.298  1.0
  O  O8  1  0.008  0.389  0.627  1.0
  O  O9  1  0.125  0.138  0.966  1.0
  O  O10  1  0.414  0.404  0.368  1.0
  O  O11  1  0.686  0.794  0.637  1.0
  O  O12  1  0.329  0.998  0.649  1.0
  O  O13  1  0.752  0.039  0.278  1.0
[/CIF]
.
The compound described by Rb2MgFe4O7 crystallizes in the triclinic P1 space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), one O(7), and two equivalent O(3) atoms. In the second Rb site, Rb(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(5), one O(6), one O(7), and two equivalent O(3) atoms. Mg(1) is bonded to one O(1), one O(3), one O(4), and one O(7) atom to form MgO4 tetrahedra that share  a cornercorner with one Fe(2)O4 tetrahedra, corners with two equivalent Fe(3)O5 trigonal bipyramids,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(1)O4 trigonal pyramid. There are four inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(1), one O(4), one O(5), and one O(7) atom to form distorted FeO4 trigonal pyramids that share  a cornercorner with one Mg(1)O4 tetrahedra,  a cornercorner with one Fe(2)O4 tetrahedra,  a cornercorner with one Fe(3)O5 trigonal bipyramid,  an edgeedge with one Mg(1)O4 tetrahedra, and  an edgeedge with one Fe(3)O5 trigonal bipyramid. In the second Fe site, Fe(2) is bonded to one O(2), one O(3), one O(5), and one O(6) atom to form FeO4 tetrahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Fe(3)O5 trigonal bipyramids, and  a cornercorner with one Fe(1)O4 trigonal pyramid. In the third Fe site, Fe(3) is bonded to one O(1), one O(2), one O(4), one O(5), and one O(6) atom to form distorted FeO5 trigonal bipyramids that share corners with two equivalent Mg(1)O4 tetrahedra, corners with three equivalent Fe(2)O4 tetrahedra,  a cornercorner with one Fe(1)O4 trigonal pyramid, and  an edgeedge with one Fe(1)O4 trigonal pyramid. In the fourth Fe site, Fe(4) is bonded in a 5-coordinate geometry to one O(2), one O(4), one O(5), one O(6), and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Rb(1), one Rb(2), one Mg(1), one Fe(1), and one Fe(3) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Rb(1), one Rb(2), one Fe(2), one Fe(3), and one Fe(4) atom. In the third O site, O(3) is bonded in a 2-coordinate geometry to two equivalent Rb(1), two equivalent Rb(2), one Mg(1), and one Fe(2) atom. In the fourth O site, O(4) is bonded in a distorted see-saw-like geometry to one Rb(1), one Mg(1), one Fe(1), one Fe(3), and one Fe(4) atom. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Rb(1), one Rb(2), one Fe(1), one Fe(2), one Fe(3), and one Fe(4) atom. In the sixth O site, O(6) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Fe(2), one Fe(3), and one Fe(4) atom. In the seventh O site, O(7) is bonded in a 5-coordinate geometry to one Rb(1), one Rb(2), one Mg(1), one Fe(1), and one Fe(4) atom. is represented by the CIF file [CIF]
data_Rb2MgFe4O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.526
_cell_length_b   5.522
_cell_length_c   7.471
_cell_angle_alpha   90.197
_cell_angle_beta   98.178
_cell_angle_gamma   112.650
_symmetry_Int_Tables_number   1
_cell_volume   207.802
_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  0.363  0.734  0.995  1.0
  Rb  Rb1  1  0.714  0.374  0.937  1.0
  Mg  Mg2  1  0.115  0.117  0.224  1.0
  Fe  Fe3  1  0.772  0.712  0.385  1.0
  Fe  Fe4  1  0.039  0.065  0.716  1.0
  Fe  Fe5  1  0.288  0.647  0.514  1.0
  Fe  Fe6  1  0.614  0.163  0.479  1.0
  O  O7  1  0.107  0.750  0.298  1.0
  O  O8  1  0.008  0.389  0.627  1.0
  O  O9  1  0.125  0.138  0.966  1.0
  O  O10  1  0.414  0.404  0.368  1.0
  O  O11  1  0.686  0.794  0.637  1.0
  O  O12  1  0.329  0.998  0.649  1.0
  O  O13  1  0.752  0.039  0.278  1.0
[/CIF]
.