The compound described by MgCo(NiO2)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Ni(4)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Ni(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Co(1), one Ni(2), one Ni(3), and one Ni(4) atom to form OMgCoNi3 square pyramids that share corners with five equivalent O(1)MgCoNi3 square pyramids and edges with four equivalent O(3)MgNi4 square pyramids. In the second O site, O(2) is bonded in a see-saw-like geometry to one Mg(1), one Co(1), one Ni(1), and one Ni(4) atom. In the third O site, O(3) is bonded to one Mg(1), one Ni(1), one Ni(2), one Ni(3), and one Ni(4) atom to form OMgNi4 square pyramids that share corners with five equivalent O(3)MgNi4 square pyramids and edges with four equivalent O(1)MgCoNi3 square pyramids. In the fourth O site, O(4) is bonded in a see-saw-like geometry to one Co(1), one Ni(1), one Ni(2), and one Ni(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCo(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.286
_cell_length_b   10.319
_cell_length_c   14.609
_cell_angle_alpha   18.940
_cell_angle_beta   19.415
_cell_angle_gamma   33.178
_symmetry_Int_Tables_number   1
_cell_volume   143.848
_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  0.500  0.000  0.500  1.0
  Co  Co1  1  0.500  0.500  0.000  1.0
  Ni  Ni2  1  0.000  0.500  0.000  1.0
  Ni  Ni3  1  0.000  0.000  0.000  1.0
  Ni  Ni4  1  0.000  0.000  0.500  1.0
  Ni  Ni5  1  0.500  0.000  0.000  1.0
  O  O6  1  0.957  0.500  0.772  1.0
  O  O7  1  0.043  0.500  0.228  1.0
  O  O8  1  0.959  0.999  0.293  1.0
  O  O9  1  0.041  0.001  0.707  1.0
  O  O10  1  0.450  0.500  0.775  1.0
  O  O11  1  0.550  0.500  0.225  1.0
  O  O12  1  0.541  0.999  0.709  1.0
  O  O13  1  0.459  0.001  0.291  1.0
[/CIF]
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The compound described by MgCo(NiO2)4 crystallizes in the triclinic P-1 space group. Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Ni(4)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. There are four inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the second Ni site, Ni(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Ni(3)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. In the fourth Ni site, Ni(4) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Co(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 10-14°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), one Co(1), one Ni(2), one Ni(3), and one Ni(4) atom to form OMgCoNi3 square pyramids that share corners with five equivalent O(1)MgCoNi3 square pyramids and edges with four equivalent O(3)MgNi4 square pyramids. In the second O site, O(2) is bonded in a see-saw-like geometry to one Mg(1), one Co(1), one Ni(1), and one Ni(4) atom. In the third O site, O(3) is bonded to one Mg(1), one Ni(1), one Ni(2), one Ni(3), and one Ni(4) atom to form OMgNi4 square pyramids that share corners with five equivalent O(3)MgNi4 square pyramids and edges with four equivalent O(1)MgCoNi3 square pyramids. In the fourth O site, O(4) is bonded in a see-saw-like geometry to one Co(1), one Ni(1), one Ni(2), and one Ni(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgCo(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.286
_cell_length_b   10.319
_cell_length_c   14.609
_cell_angle_alpha   18.940
_cell_angle_beta   19.415
_cell_angle_gamma   33.178
_symmetry_Int_Tables_number   1
_cell_volume   143.848
_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  0.500  0.000  0.500  1.0
  Co  Co1  1  0.500  0.500  0.000  1.0
  Ni  Ni2  1  0.000  0.500  0.000  1.0
  Ni  Ni3  1  0.000  0.000  0.000  1.0
  Ni  Ni4  1  0.000  0.000  0.500  1.0
  Ni  Ni5  1  0.500  0.000  0.000  1.0
  O  O6  1  0.957  0.500  0.772  1.0
  O  O7  1  0.043  0.500  0.228  1.0
  O  O8  1  0.959  0.999  0.293  1.0
  O  O9  1  0.041  0.001  0.707  1.0
  O  O10  1  0.450  0.500  0.775  1.0
  O  O11  1  0.550  0.500  0.225  1.0
  O  O12  1  0.541  0.999  0.709  1.0
  O  O13  1  0.459  0.001  0.291  1.0
[/CIF]
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