The material described by Mg(NiO2)2 crystallizes in the orthorhombic Pbcm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Ni(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 8-55°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and three equivalent Ni(1) atoms to form distorted OMg2Ni3 trigonal bipyramids that share corners with four equivalent O(2)Mg2Ni4 octahedra, corners with five equivalent O(3)Mg2Ni2 tetrahedra, corners with two equivalent O(1)Mg2Ni3 trigonal bipyramids, edges with three equivalent O(2)Mg2Ni4 octahedra,  an edgeedge with one O(3)Mg2Ni2 tetrahedra, and edges with five equivalent O(1)Mg2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 7-46°. In the second O site, O(2) is bonded to two equivalent Mg(1) and four equivalent Ni(1) atoms to form distorted OMg2Ni4 octahedra that share corners with two equivalent O(2)Mg2Ni4 octahedra, corners with eight equivalent O(1)Mg2Ni3 trigonal bipyramids, edges with two equivalent O(2)Mg2Ni4 octahedra, edges with four equivalent O(3)Mg2Ni2 tetrahedra, and edges with six equivalent O(1)Mg2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. In the third O site, O(3) is bonded to two equivalent Mg(1) and two equivalent Ni(1) atoms to form OMg2Ni2 tetrahedra that share corners with two equivalent O(3)Mg2Ni2 tetrahedra, corners with ten equivalent O(1)Mg2Ni3 trigonal bipyramids, edges with four equivalent O(2)Mg2Ni4 octahedra, and edges with two equivalent O(1)Mg2Ni3 trigonal bipyramids. is represented by the CIF file [CIF]
data_Mg(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.928
_cell_length_b   9.289
_cell_length_c   9.529
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   259.139
_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  0.804  0.250  0.853  1.0
  Mg  Mg1  1  0.804  0.750  0.647  1.0
  Mg  Mg2  1  0.196  0.250  0.353  1.0
  Mg  Mg3  1  0.196  0.750  0.147  1.0
  Ni  Ni4  1  0.276  0.070  0.613  1.0
  Ni  Ni5  1  0.276  0.570  0.887  1.0
  Ni  Ni6  1  0.724  0.570  0.387  1.0
  Ni  Ni7  1  0.276  0.930  0.887  1.0
  Ni  Ni8  1  0.724  0.930  0.387  1.0
  Ni  Ni9  1  0.276  0.430  0.613  1.0
  Ni  Ni10  1  0.724  0.430  0.113  1.0
  Ni  Ni11  1  0.724  0.070  0.113  1.0
  O  O12  1  0.723  0.387  0.473  1.0
  O  O13  1  0.277  0.613  0.527  1.0
  O  O14  1  0.849  0.500  0.750  1.0
  O  O15  1  0.277  0.387  0.973  1.0
  O  O16  1  0.277  0.113  0.973  1.0
  O  O17  1  0.303  0.750  0.795  1.0
  O  O18  1  0.723  0.613  0.027  1.0
  O  O19  1  0.697  0.750  0.295  1.0
  O  O20  1  0.849  0.000  0.750  1.0
  O  O21  1  0.151  0.500  0.250  1.0
  O  O22  1  0.723  0.113  0.473  1.0
  O  O23  1  0.697  0.250  0.205  1.0
  O  O24  1  0.303  0.250  0.705  1.0
  O  O25  1  0.151  0.000  0.250  1.0
  O  O26  1  0.723  0.887  0.027  1.0
  O  O27  1  0.277  0.887  0.527  1.0
[/CIF]
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The material described by Mg(NiO2)2 crystallizes in the orthorhombic Pbcm space group. Mg(1) is bonded in a 8-coordinate geometry to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms. Ni(1) is bonded to one O(3), two equivalent O(2), and three equivalent O(1) atoms to form a mixture of edge and corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 8-55°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Mg(1) and three equivalent Ni(1) atoms to form distorted OMg2Ni3 trigonal bipyramids that share corners with four equivalent O(2)Mg2Ni4 octahedra, corners with five equivalent O(3)Mg2Ni2 tetrahedra, corners with two equivalent O(1)Mg2Ni3 trigonal bipyramids, edges with three equivalent O(2)Mg2Ni4 octahedra,  an edgeedge with one O(3)Mg2Ni2 tetrahedra, and edges with five equivalent O(1)Mg2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 7-46°. In the second O site, O(2) is bonded to two equivalent Mg(1) and four equivalent Ni(1) atoms to form distorted OMg2Ni4 octahedra that share corners with two equivalent O(2)Mg2Ni4 octahedra, corners with eight equivalent O(1)Mg2Ni3 trigonal bipyramids, edges with two equivalent O(2)Mg2Ni4 octahedra, edges with four equivalent O(3)Mg2Ni2 tetrahedra, and edges with six equivalent O(1)Mg2Ni3 trigonal bipyramids. The corner-sharing octahedral tilt angles are 46°. In the third O site, O(3) is bonded to two equivalent Mg(1) and two equivalent Ni(1) atoms to form OMg2Ni2 tetrahedra that share corners with two equivalent O(3)Mg2Ni2 tetrahedra, corners with ten equivalent O(1)Mg2Ni3 trigonal bipyramids, edges with four equivalent O(2)Mg2Ni4 octahedra, and edges with two equivalent O(1)Mg2Ni3 trigonal bipyramids. is represented by the CIF file [CIF]
data_Mg(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.928
_cell_length_b   9.289
_cell_length_c   9.529
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   259.139
_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  0.804  0.250  0.853  1.0
  Mg  Mg1  1  0.804  0.750  0.647  1.0
  Mg  Mg2  1  0.196  0.250  0.353  1.0
  Mg  Mg3  1  0.196  0.750  0.147  1.0
  Ni  Ni4  1  0.276  0.070  0.613  1.0
  Ni  Ni5  1  0.276  0.570  0.887  1.0
  Ni  Ni6  1  0.724  0.570  0.387  1.0
  Ni  Ni7  1  0.276  0.930  0.887  1.0
  Ni  Ni8  1  0.724  0.930  0.387  1.0
  Ni  Ni9  1  0.276  0.430  0.613  1.0
  Ni  Ni10  1  0.724  0.430  0.113  1.0
  Ni  Ni11  1  0.724  0.070  0.113  1.0
  O  O12  1  0.723  0.387  0.473  1.0
  O  O13  1  0.277  0.613  0.527  1.0
  O  O14  1  0.849  0.500  0.750  1.0
  O  O15  1  0.277  0.387  0.973  1.0
  O  O16  1  0.277  0.113  0.973  1.0
  O  O17  1  0.303  0.750  0.795  1.0
  O  O18  1  0.723  0.613  0.027  1.0
  O  O19  1  0.697  0.750  0.295  1.0
  O  O20  1  0.849  0.000  0.750  1.0
  O  O21  1  0.151  0.500  0.250  1.0
  O  O22  1  0.723  0.113  0.473  1.0
  O  O23  1  0.697  0.250  0.205  1.0
  O  O24  1  0.303  0.250  0.705  1.0
  O  O25  1  0.151  0.000  0.250  1.0
  O  O26  1  0.723  0.887  0.027  1.0
  O  O27  1  0.277  0.887  0.527  1.0
[/CIF]
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