The structure described by MgCoO2 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted corner-sharing CoO4 trigonal pyramids. In the second Co site, Co(2) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form distorted corner-sharing CoO4 trigonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Co(2), and two equivalent Co(1) atoms to form distorted OMg2Co3 square pyramids that share corners with four equivalent O(3)Mg4Co square pyramids,  an edgeedge with one O(3)Mg4Co square pyramid, edges with two equivalent O(1)Mg2Co3 square pyramids, and edges with two equivalent O(4)Mg2Co2 tetrahedra. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2), one Co(1), and one Co(2) atom. In the third O site, O(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), and one Co(1) atom to form OMg4Co square pyramids that share corners with four equivalent O(1)Mg2Co3 square pyramids, corners with four equivalent O(4)Mg2Co2 tetrahedra,  an edgeedge with one O(1)Mg2Co3 square pyramid, and edges with two equivalent O(3)Mg4Co square pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), and two equivalent Co(2) atoms to form OMg2Co2 tetrahedra that share corners with four equivalent O(3)Mg4Co square pyramids, corners with two equivalent O(4)Mg2Co2 tetrahedra, and edges with two equivalent O(1)Mg2Co3 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCoO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.040
_cell_length_b   8.022
_cell_length_c   8.162
_cell_angle_alpha   86.420
_cell_angle_beta   88.963
_cell_angle_gamma   79.380
_symmetry_Int_Tables_number   1
_cell_volume   195.291
_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  0.148  0.209  0.947  1.0
  Mg  Mg1  1  0.852  0.791  0.053  1.0
  Mg  Mg2  1  0.049  0.378  0.250  1.0
  Mg  Mg3  1  0.951  0.622  0.750  1.0
  Co  Co4  1  0.307  0.925  0.729  1.0
  Co  Co5  1  0.634  0.273  0.638  1.0
  Co  Co6  1  0.366  0.727  0.362  1.0
  Co  Co7  1  0.693  0.075  0.271  1.0
  O  O8  1  0.262  0.943  0.186  1.0
  O  O9  1  0.404  0.733  0.594  1.0
  O  O10  1  0.596  0.267  0.406  1.0
  O  O11  1  0.738  0.057  0.814  1.0
  O  O12  1  0.396  0.718  0.907  1.0
  O  O13  1  0.079  0.374  0.747  1.0
  O  O14  1  0.604  0.282  0.093  1.0
  O  O15  1  0.921  0.626  0.253  1.0
[/CIF]
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The structure described by MgCoO2 crystallizes in the triclinic P-1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Mg site, Mg(2) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(2), and two equivalent O(3) atoms. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form distorted corner-sharing CoO4 trigonal pyramids. In the second Co site, Co(2) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form distorted corner-sharing CoO4 trigonal pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1), one Co(2), and two equivalent Co(1) atoms to form distorted OMg2Co3 square pyramids that share corners with four equivalent O(3)Mg4Co square pyramids,  an edgeedge with one O(3)Mg4Co square pyramid, edges with two equivalent O(1)Mg2Co3 square pyramids, and edges with two equivalent O(4)Mg2Co2 tetrahedra. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2), one Co(1), and one Co(2) atom. In the third O site, O(3) is bonded to two equivalent Mg(1), two equivalent Mg(2), and one Co(1) atom to form OMg4Co square pyramids that share corners with four equivalent O(1)Mg2Co3 square pyramids, corners with four equivalent O(4)Mg2Co2 tetrahedra,  an edgeedge with one O(1)Mg2Co3 square pyramid, and edges with two equivalent O(3)Mg4Co square pyramids. In the fourth O site, O(4) is bonded to one Mg(1), one Mg(2), and two equivalent Co(2) atoms to form OMg2Co2 tetrahedra that share corners with four equivalent O(3)Mg4Co square pyramids, corners with two equivalent O(4)Mg2Co2 tetrahedra, and edges with two equivalent O(1)Mg2Co3 square pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCoO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.040
_cell_length_b   8.022
_cell_length_c   8.162
_cell_angle_alpha   86.420
_cell_angle_beta   88.963
_cell_angle_gamma   79.380
_symmetry_Int_Tables_number   1
_cell_volume   195.291
_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  0.148  0.209  0.947  1.0
  Mg  Mg1  1  0.852  0.791  0.053  1.0
  Mg  Mg2  1  0.049  0.378  0.250  1.0
  Mg  Mg3  1  0.951  0.622  0.750  1.0
  Co  Co4  1  0.307  0.925  0.729  1.0
  Co  Co5  1  0.634  0.273  0.638  1.0
  Co  Co6  1  0.366  0.727  0.362  1.0
  Co  Co7  1  0.693  0.075  0.271  1.0
  O  O8  1  0.262  0.943  0.186  1.0
  O  O9  1  0.404  0.733  0.594  1.0
  O  O10  1  0.596  0.267  0.406  1.0
  O  O11  1  0.738  0.057  0.814  1.0
  O  O12  1  0.396  0.718  0.907  1.0
  O  O13  1  0.079  0.374  0.747  1.0
  O  O14  1  0.604  0.282  0.093  1.0
  O  O15  1  0.921  0.626  0.253  1.0
[/CIF]
.