The crystal structure described by MgNiO2 crystallizes in the triclinic P-1 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 two equivalent O(4) atoms to form distorted MgO5 trigonal bipyramids that share corners with four equivalent Mg(2)O4 tetrahedra, corners with two equivalent Ni(2)O5 trigonal bipyramids, edges with two equivalent Mg(1)O5 trigonal bipyramids, and  a faceface with one Ni(2)O5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form MgO4 tetrahedra that share corners with two equivalent Mg(2)O4 tetrahedra, corners with four equivalent Mg(1)O5 trigonal bipyramids, corners with four equivalent Ni(2)O5 trigonal bipyramids, and  an edgeedge with one Ni(2)O5 trigonal bipyramid. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Ni site, Ni(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted NiO5 trigonal bipyramids that share corners with four equivalent Mg(2)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids,  an edgeedge with one Mg(2)O4 tetrahedra, edges with two equivalent Ni(2)O5 trigonal bipyramids, and  a faceface with one Mg(1)O5 trigonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ni(2), and two equivalent Ni(1) atoms to form OMgNi3 tetrahedra that share corners with two equivalent O(1)MgNi3 tetrahedra, corners with four equivalent O(3)Mg3Ni2 trigonal bipyramids, and  an edgeedge with one O(3)Mg3Ni2 trigonal bipyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2) and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and two equivalent Ni(1) atoms to form distorted OMg3Ni2 trigonal bipyramids that share corners with four equivalent O(1)MgNi3 tetrahedra,  an edgeedge with one O(1)MgNi3 tetrahedra, and edges with two equivalent O(3)Mg3Ni2 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent Ni(2) atoms. is represented by the CIF file [CIF]
data_MgNiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.887
_cell_length_b   8.143
_cell_length_c   8.413
_cell_angle_alpha   83.354
_cell_angle_beta   80.180
_cell_angle_gamma   80.042
_symmetry_Int_Tables_number   1
_cell_volume   191.194
_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  0.845  0.228  0.572  1.0
  Mg  Mg1  1  0.155  0.772  0.428  1.0
  Mg  Mg2  1  0.579  0.131  0.209  1.0
  Mg  Mg3  1  0.421  0.869  0.791  1.0
  Ni  Ni4  1  0.129  0.554  0.692  1.0
  Ni  Ni5  1  0.712  0.190  0.883  1.0
  Ni  Ni6  1  0.288  0.810  0.117  1.0
  Ni  Ni7  1  0.871  0.446  0.308  1.0
  O  O8  1  0.319  0.595  0.266  1.0
  O  O9  1  0.867  0.822  0.946  1.0
  O  O10  1  0.133  0.178  0.054  1.0
  O  O11  1  0.681  0.405  0.734  1.0
  O  O12  1  0.589  0.719  0.611  1.0
  O  O13  1  0.336  0.106  0.711  1.0
  O  O14  1  0.411  0.281  0.389  1.0
  O  O15  1  0.664  0.894  0.289  1.0
[/CIF]
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The crystal structure described by MgNiO2 crystallizes in the triclinic P-1 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 two equivalent O(4) atoms to form distorted MgO5 trigonal bipyramids that share corners with four equivalent Mg(2)O4 tetrahedra, corners with two equivalent Ni(2)O5 trigonal bipyramids, edges with two equivalent Mg(1)O5 trigonal bipyramids, and  a faceface with one Ni(2)O5 trigonal bipyramid. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form MgO4 tetrahedra that share corners with two equivalent Mg(2)O4 tetrahedra, corners with four equivalent Mg(1)O5 trigonal bipyramids, corners with four equivalent Ni(2)O5 trigonal bipyramids, and  an edgeedge with one Ni(2)O5 trigonal bipyramid. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(1) and two equivalent O(3) atoms. In the second Ni site, Ni(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted NiO5 trigonal bipyramids that share corners with four equivalent Mg(2)O4 tetrahedra, corners with two equivalent Mg(1)O5 trigonal bipyramids,  an edgeedge with one Mg(2)O4 tetrahedra, edges with two equivalent Ni(2)O5 trigonal bipyramids, and  a faceface with one Mg(1)O5 trigonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Ni(2), and two equivalent Ni(1) atoms to form OMgNi3 tetrahedra that share corners with two equivalent O(1)MgNi3 tetrahedra, corners with four equivalent O(3)Mg3Ni2 trigonal bipyramids, and  an edgeedge with one O(3)Mg3Ni2 trigonal bipyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(2) and two equivalent Ni(2) atoms. In the third O site, O(3) is bonded to one Mg(2), two equivalent Mg(1), and two equivalent Ni(1) atoms to form distorted OMg3Ni2 trigonal bipyramids that share corners with four equivalent O(1)MgNi3 tetrahedra,  an edgeedge with one O(1)MgNi3 tetrahedra, and edges with two equivalent O(3)Mg3Ni2 trigonal bipyramids. In the fourth O site, O(4) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), and two equivalent Ni(2) atoms. is represented by the CIF file [CIF]
data_MgNiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.887
_cell_length_b   8.143
_cell_length_c   8.413
_cell_angle_alpha   83.354
_cell_angle_beta   80.180
_cell_angle_gamma   80.042
_symmetry_Int_Tables_number   1
_cell_volume   191.194
_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  0.845  0.228  0.572  1.0
  Mg  Mg1  1  0.155  0.772  0.428  1.0
  Mg  Mg2  1  0.579  0.131  0.209  1.0
  Mg  Mg3  1  0.421  0.869  0.791  1.0
  Ni  Ni4  1  0.129  0.554  0.692  1.0
  Ni  Ni5  1  0.712  0.190  0.883  1.0
  Ni  Ni6  1  0.288  0.810  0.117  1.0
  Ni  Ni7  1  0.871  0.446  0.308  1.0
  O  O8  1  0.319  0.595  0.266  1.0
  O  O9  1  0.867  0.822  0.946  1.0
  O  O10  1  0.133  0.178  0.054  1.0
  O  O11  1  0.681  0.405  0.734  1.0
  O  O12  1  0.589  0.719  0.611  1.0
  O  O13  1  0.336  0.106  0.711  1.0
  O  O14  1  0.411  0.281  0.389  1.0
  O  O15  1  0.664  0.894  0.289  1.0
[/CIF]
.