The structure described by Bi2MgO4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO5 square pyramids that share corners with six equivalent Bi(1)O5 square pyramids,  an edgeedge with one Bi(1)O5 square pyramid, and edges with two equivalent Mg(1)O5 square pyramids. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted BiO5 square pyramids that share corners with six equivalent Mg(1)O5 square pyramids,  an edgeedge with one Mg(1)O5 square pyramid, and edges with two equivalent Bi(1)O5 square pyramids. In the second Bi site, Bi(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), and three equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to three equivalent Bi(2) atoms. In the second O site, O(2) is bonded to one Mg(1), one Bi(2), and two equivalent Bi(1) atoms to form distorted OMgBi3 tetrahedra that share corners with five equivalent O(3)Mg2Bi3 square pyramids, corners with two equivalent O(2)MgBi3 tetrahedra, and  an edgeedge with one O(3)Mg2Bi3 square pyramid. In the third O site, O(3) is bonded to two equivalent Mg(1), one Bi(2), and two equivalent Bi(1) atoms to form distorted OMg2Bi3 square pyramids that share corners with five equivalent O(2)MgBi3 tetrahedra, edges with two equivalent O(3)Mg2Bi3 square pyramids, and  an edgeedge with one O(2)MgBi3 tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one Bi(1) atom. is represented by the CIF file [CIF]
data_Mg(BiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.360
_cell_length_b   10.672
_cell_length_c   11.619
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   416.669
_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
  Mg  Mg0  1  0.250  0.218  0.857  1.0
  Mg  Mg1  1  0.750  0.782  0.143  1.0
  Mg  Mg2  1  0.250  0.718  0.643  1.0
  Mg  Mg3  1  0.750  0.282  0.357  1.0
  Bi  Bi4  1  0.750  0.418  0.622  1.0
  Bi  Bi5  1  0.250  0.082  0.122  1.0
  Bi  Bi6  1  0.750  0.918  0.878  1.0
  Bi  Bi7  1  0.250  0.582  0.378  1.0
  Bi  Bi8  1  0.250  0.600  0.898  1.0
  Bi  Bi9  1  0.750  0.400  0.102  1.0
  Bi  Bi10  1  0.250  0.100  0.602  1.0
  Bi  Bi11  1  0.750  0.900  0.398  1.0
  O  O12  1  0.750  0.965  0.590  1.0
  O  O13  1  0.250  0.035  0.410  1.0
  O  O14  1  0.750  0.465  0.910  1.0
  O  O15  1  0.250  0.535  0.090  1.0
  O  O16  1  0.750  0.967  0.201  1.0
  O  O17  1  0.250  0.033  0.799  1.0
  O  O18  1  0.750  0.467  0.299  1.0
  O  O19  1  0.250  0.533  0.701  1.0
  O  O20  1  0.750  0.693  0.523  1.0
  O  O21  1  0.250  0.307  0.477  1.0
  O  O22  1  0.750  0.193  0.977  1.0
  O  O23  1  0.250  0.807  0.023  1.0
  O  O24  1  0.250  0.741  0.263  1.0
  O  O25  1  0.750  0.259  0.737  1.0
  O  O26  1  0.750  0.759  0.763  1.0
  O  O27  1  0.250  0.241  0.237  1.0
[/CIF]
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The structure described by Bi2MgO4 crystallizes in the orthorhombic Pnma space group. Mg(1) is bonded to one O(2), two equivalent O(3), and two equivalent O(4) atoms to form MgO5 square pyramids that share corners with six equivalent Bi(1)O5 square pyramids,  an edgeedge with one Bi(1)O5 square pyramid, and edges with two equivalent Mg(1)O5 square pyramids. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form distorted BiO5 square pyramids that share corners with six equivalent Mg(1)O5 square pyramids,  an edgeedge with one Mg(1)O5 square pyramid, and edges with two equivalent Bi(1)O5 square pyramids. In the second Bi site, Bi(2) is bonded in a 5-coordinate geometry to one O(2), one O(3), and three equivalent O(1) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal non-coplanar geometry to three equivalent Bi(2) atoms. In the second O site, O(2) is bonded to one Mg(1), one Bi(2), and two equivalent Bi(1) atoms to form distorted OMgBi3 tetrahedra that share corners with five equivalent O(3)Mg2Bi3 square pyramids, corners with two equivalent O(2)MgBi3 tetrahedra, and  an edgeedge with one O(3)Mg2Bi3 square pyramid. In the third O site, O(3) is bonded to two equivalent Mg(1), one Bi(2), and two equivalent Bi(1) atoms to form distorted OMg2Bi3 square pyramids that share corners with five equivalent O(2)MgBi3 tetrahedra, edges with two equivalent O(3)Mg2Bi3 square pyramids, and  an edgeedge with one O(2)MgBi3 tetrahedra. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one Bi(1) atom. is represented by the CIF file [CIF]
data_Mg(BiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.360
_cell_length_b   10.672
_cell_length_c   11.619
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   416.669
_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
  Mg  Mg0  1  0.250  0.218  0.857  1.0
  Mg  Mg1  1  0.750  0.782  0.143  1.0
  Mg  Mg2  1  0.250  0.718  0.643  1.0
  Mg  Mg3  1  0.750  0.282  0.357  1.0
  Bi  Bi4  1  0.750  0.418  0.622  1.0
  Bi  Bi5  1  0.250  0.082  0.122  1.0
  Bi  Bi6  1  0.750  0.918  0.878  1.0
  Bi  Bi7  1  0.250  0.582  0.378  1.0
  Bi  Bi8  1  0.250  0.600  0.898  1.0
  Bi  Bi9  1  0.750  0.400  0.102  1.0
  Bi  Bi10  1  0.250  0.100  0.602  1.0
  Bi  Bi11  1  0.750  0.900  0.398  1.0
  O  O12  1  0.750  0.965  0.590  1.0
  O  O13  1  0.250  0.035  0.410  1.0
  O  O14  1  0.750  0.465  0.910  1.0
  O  O15  1  0.250  0.535  0.090  1.0
  O  O16  1  0.750  0.967  0.201  1.0
  O  O17  1  0.250  0.033  0.799  1.0
  O  O18  1  0.750  0.467  0.299  1.0
  O  O19  1  0.250  0.533  0.701  1.0
  O  O20  1  0.750  0.693  0.523  1.0
  O  O21  1  0.250  0.307  0.477  1.0
  O  O22  1  0.750  0.193  0.977  1.0
  O  O23  1  0.250  0.807  0.023  1.0
  O  O24  1  0.250  0.741  0.263  1.0
  O  O25  1  0.750  0.259  0.737  1.0
  O  O26  1  0.750  0.759  0.763  1.0
  O  O27  1  0.250  0.241  0.237  1.0
[/CIF]
.