The compound described by MgCo2O4 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with twelve equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and faces with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. Co(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted CoO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with six equivalent Co(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Mg(1) and three equivalent Co(1) atoms. In the second O site, O(2) is bonded to one Mg(1) and three equivalent Co(1) atoms to form a mixture of corner and edge-sharing OMgCo3 trigonal pyramids. is represented by the CIF file [CIF]
data_Mg(CoO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.031
_cell_length_b   5.826
_cell_length_c   4.963
_cell_angle_alpha   118.044
_cell_angle_beta   89.989
_cell_angle_gamma   74.945
_symmetry_Int_Tables_number   1
_cell_volume   73.925
_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
  Mg  Mg0  1  0.256  0.491  0.727  1.0
  Co  Co1  1  0.972  0.059  0.007  1.0
  Co  Co2  1  0.540  0.923  0.446  1.0
  O  O3  1  0.892  0.220  0.434  1.0
  O  O4  1  0.392  0.218  0.893  1.0
  O  O5  1  0.119  0.764  0.560  1.0
  O  O6  1  0.620  0.763  0.020  1.0
[/CIF]
.
The compound described by MgCo2O4 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with twelve equivalent Co(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and faces with two equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. Co(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form distorted CoO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with six equivalent Co(1)O6 octahedra, and  a faceface with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 42-56°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 5-coordinate geometry to two equivalent Mg(1) and three equivalent Co(1) atoms. In the second O site, O(2) is bonded to one Mg(1) and three equivalent Co(1) atoms to form a mixture of corner and edge-sharing OMgCo3 trigonal pyramids. is represented by the CIF file [CIF]
data_Mg(CoO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.031
_cell_length_b   5.826
_cell_length_c   4.963
_cell_angle_alpha   118.044
_cell_angle_beta   89.989
_cell_angle_gamma   74.945
_symmetry_Int_Tables_number   1
_cell_volume   73.925
_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
  Mg  Mg0  1  0.256  0.491  0.727  1.0
  Co  Co1  1  0.972  0.059  0.007  1.0
  Co  Co2  1  0.540  0.923  0.446  1.0
  O  O3  1  0.892  0.220  0.434  1.0
  O  O4  1  0.392  0.218  0.893  1.0
  O  O5  1  0.119  0.764  0.560  1.0
  O  O6  1  0.620  0.763  0.020  1.0
[/CIF]
.