The structure described by MgMnO2 is Caswellsilverite-like structured and crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), two equivalent O(3), and three equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second Mg site, Mg(2) is bonded to one O(3), two equivalent O(4), and three equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Mn(2)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-4°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-4°. In the second Mn site, Mn(2) is bonded to one O(4), two equivalent O(2), and three equivalent O(1) atoms to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mn(1), and three equivalent Mn(2) atoms to form OMgMn5 octahedra that share corners with two equivalent O(2)Mg3Mn3 octahedra, corners with two equivalent O(3)Mg3Mn3 octahedra, corners with two equivalent O(4)Mg5Mn octahedra, edges with two equivalent O(4)Mg5Mn octahedra, edges with three equivalent O(2)Mg3Mn3 octahedra, edges with three equivalent O(3)Mg3Mn3 octahedra, and edges with four equivalent O(1)MgMn5 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second O site, O(2) is bonded to three equivalent Mg(2), one Mn(1), and two equivalent Mn(2) atoms to form OMg3Mn3 octahedra that share corners with two equivalent O(3)Mg3Mn3 octahedra, corners with two equivalent O(4)Mg5Mn octahedra, corners with two equivalent O(1)MgMn5 octahedra, edges with two equivalent O(3)Mg3Mn3 octahedra, edges with three equivalent O(4)Mg5Mn octahedra, edges with three equivalent O(1)MgMn5 octahedra, and edges with four equivalent O(2)Mg3Mn3 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and three equivalent Mn(1) atoms to form OMg3Mn3 octahedra that share corners with two equivalent O(2)Mg3Mn3 octahedra, corners with two equivalent O(4)Mg5Mn octahedra, corners with two equivalent O(1)MgMn5 octahedra, edges with two equivalent O(2)Mg3Mn3 octahedra, edges with three equivalent O(4)Mg5Mn octahedra, edges with three equivalent O(1)MgMn5 octahedra, and edges with four equivalent O(3)Mg3Mn3 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the fourth O site, O(4) is bonded to two equivalent Mg(2), three equivalent Mg(1), and one Mn(2) atom to form OMg5Mn octahedra that share corners with two equivalent O(2)Mg3Mn3 octahedra, corners with two equivalent O(3)Mg3Mn3 octahedra, corners with two equivalent O(1)MgMn5 octahedra, edges with two equivalent O(1)MgMn5 octahedra, edges with three equivalent O(2)Mg3Mn3 octahedra, edges with three equivalent O(3)Mg3Mn3 octahedra, and edges with four equivalent O(4)Mg5Mn octahedra. The corner-sharing octahedral tilt angles range from 1-2°. is represented by the CIF file [CIF]
data_MgMnO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.099
_cell_length_b   7.593
_cell_length_c   7.616
_cell_angle_alpha   70.574
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   168.997
_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  0.439  0.183  1.0
  Mg  Mg1  1  0.750  0.561  0.817  1.0
  Mg  Mg2  1  0.750  0.810  0.062  1.0
  Mg  Mg3  1  0.250  0.190  0.938  1.0
  Mn  Mn4  1  0.750  0.315  0.563  1.0
  Mn  Mn5  1  0.750  0.063  0.306  1.0
  Mn  Mn6  1  0.250  0.937  0.694  1.0
  Mn  Mn7  1  0.250  0.685  0.437  1.0
  O  O8  1  0.750  0.806  0.571  1.0
  O  O9  1  0.750  0.064  0.824  1.0
  O  O10  1  0.250  0.936  0.176  1.0
  O  O11  1  0.250  0.194  0.429  1.0
  O  O12  1  0.250  0.438  0.700  1.0
  O  O13  1  0.750  0.318  0.056  1.0
  O  O14  1  0.750  0.562  0.300  1.0
  O  O15  1  0.250  0.682  0.944  1.0
[/CIF]
.
The structure described by MgMnO2 is Caswellsilverite-like structured and crystallizes in the monoclinic P2_1/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), two equivalent O(3), and three equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(2)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second Mg site, Mg(2) is bonded to one O(3), two equivalent O(4), and three equivalent O(2) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mn(1)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Mn(2)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-4°. There are two inequivalent Mn sites. In the first Mn site, Mn(1) is bonded to one O(2), two equivalent O(1), and three equivalent O(3) atoms to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Mn(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with three equivalent Mg(1)O6 octahedra, edges with three equivalent Mn(2)O6 octahedra, and edges with four equivalent Mn(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-4°. In the second Mn site, Mn(2) is bonded to one O(4), two equivalent O(2), and three equivalent O(1) atoms to form MnO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Mn(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with three equivalent Mg(2)O6 octahedra, edges with three equivalent Mn(1)O6 octahedra, and edges with four equivalent Mn(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mn(1), and three equivalent Mn(2) atoms to form OMgMn5 octahedra that share corners with two equivalent O(2)Mg3Mn3 octahedra, corners with two equivalent O(3)Mg3Mn3 octahedra, corners with two equivalent O(4)Mg5Mn octahedra, edges with two equivalent O(4)Mg5Mn octahedra, edges with three equivalent O(2)Mg3Mn3 octahedra, edges with three equivalent O(3)Mg3Mn3 octahedra, and edges with four equivalent O(1)MgMn5 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the second O site, O(2) is bonded to three equivalent Mg(2), one Mn(1), and two equivalent Mn(2) atoms to form OMg3Mn3 octahedra that share corners with two equivalent O(3)Mg3Mn3 octahedra, corners with two equivalent O(4)Mg5Mn octahedra, corners with two equivalent O(1)MgMn5 octahedra, edges with two equivalent O(3)Mg3Mn3 octahedra, edges with three equivalent O(4)Mg5Mn octahedra, edges with three equivalent O(1)MgMn5 octahedra, and edges with four equivalent O(2)Mg3Mn3 octahedra. The corner-sharing octahedral tilt angles are 1°. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and three equivalent Mn(1) atoms to form OMg3Mn3 octahedra that share corners with two equivalent O(2)Mg3Mn3 octahedra, corners with two equivalent O(4)Mg5Mn octahedra, corners with two equivalent O(1)MgMn5 octahedra, edges with two equivalent O(2)Mg3Mn3 octahedra, edges with three equivalent O(4)Mg5Mn octahedra, edges with three equivalent O(1)MgMn5 octahedra, and edges with four equivalent O(3)Mg3Mn3 octahedra. The corner-sharing octahedral tilt angles range from 1-2°. In the fourth O site, O(4) is bonded to two equivalent Mg(2), three equivalent Mg(1), and one Mn(2) atom to form OMg5Mn octahedra that share corners with two equivalent O(2)Mg3Mn3 octahedra, corners with two equivalent O(3)Mg3Mn3 octahedra, corners with two equivalent O(1)MgMn5 octahedra, edges with two equivalent O(1)MgMn5 octahedra, edges with three equivalent O(2)Mg3Mn3 octahedra, edges with three equivalent O(3)Mg3Mn3 octahedra, and edges with four equivalent O(4)Mg5Mn octahedra. The corner-sharing octahedral tilt angles range from 1-2°. is represented by the CIF file [CIF]
data_MgMnO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.099
_cell_length_b   7.593
_cell_length_c   7.616
_cell_angle_alpha   70.574
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   168.997
_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  0.439  0.183  1.0
  Mg  Mg1  1  0.750  0.561  0.817  1.0
  Mg  Mg2  1  0.750  0.810  0.062  1.0
  Mg  Mg3  1  0.250  0.190  0.938  1.0
  Mn  Mn4  1  0.750  0.315  0.563  1.0
  Mn  Mn5  1  0.750  0.063  0.306  1.0
  Mn  Mn6  1  0.250  0.937  0.694  1.0
  Mn  Mn7  1  0.250  0.685  0.437  1.0
  O  O8  1  0.750  0.806  0.571  1.0
  O  O9  1  0.750  0.064  0.824  1.0
  O  O10  1  0.250  0.936  0.176  1.0
  O  O11  1  0.250  0.194  0.429  1.0
  O  O12  1  0.250  0.438  0.700  1.0
  O  O13  1  0.750  0.318  0.056  1.0
  O  O14  1  0.750  0.562  0.300  1.0
  O  O15  1  0.250  0.682  0.944  1.0
[/CIF]
.