The structure described by SrMg(NiO2)4 crystallizes in the monoclinic C2/m space group. Sr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted SrO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-20°. Mg(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra, edges with two equivalent Sr(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-17°. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Sr(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-20°. In the second Ni site, Ni(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Sr(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-17°. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share edges with two equivalent Sr(1)O6 octahedra, edges with two equivalent Mg(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. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Sr(1), one Ni(1), and two equivalent Ni(3) atoms. In the second O site, O(2) is bonded to one Sr(1), one Mg(1), one Ni(1), one Ni(2), and one Ni(3) atom to form a mixture of corner and edge-sharing OSrMgNi3 square pyramids. In the third O site, O(3) is bonded in a see-saw-like geometry to one Mg(1), one Ni(2), and two equivalent Ni(3) atoms. is represented by the CIF file [CIF]
data_SrMg(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.380
_cell_length_b   6.330
_cell_length_c   6.380
_cell_angle_alpha   55.501
_cell_angle_beta   56.263
_cell_angle_gamma   55.501
_symmetry_Int_Tables_number   1
_cell_volume   164.222
_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
  Sr  Sr0  1  0.500  0.500  0.500  1.0
  Mg  Mg1  1  0.000  0.500  0.000  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  Ni  Ni3  1  0.500  0.000  0.500  1.0
  Ni  Ni4  1  0.500  0.500  0.000  1.0
  Ni  Ni5  1  0.000  0.500  0.500  1.0
  O  O6  1  0.767  0.293  0.767  1.0
  O  O7  1  0.205  0.264  0.735  1.0
  O  O8  1  0.233  0.707  0.233  1.0
  O  O9  1  0.735  0.264  0.205  1.0
  O  O10  1  0.258  0.293  0.258  1.0
  O  O11  1  0.742  0.707  0.742  1.0
  O  O12  1  0.795  0.736  0.265  1.0
  O  O13  1  0.265  0.736  0.795  1.0
[/CIF]
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The structure described by SrMg(NiO2)4 crystallizes in the monoclinic C2/m space group. Sr(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form distorted SrO6 octahedra that share corners with six equivalent Ni(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-20°. Mg(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with six equivalent Ni(2)O6 octahedra, edges with two equivalent Sr(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-17°. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Sr(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 14-20°. In the second Ni site, Ni(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form NiO6 octahedra that share corners with six equivalent Mg(1)O6 octahedra, edges with two equivalent Sr(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Ni(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 16-17°. In the third Ni site, Ni(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share edges with two equivalent Sr(1)O6 octahedra, edges with two equivalent Mg(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. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted see-saw-like geometry to one Sr(1), one Ni(1), and two equivalent Ni(3) atoms. In the second O site, O(2) is bonded to one Sr(1), one Mg(1), one Ni(1), one Ni(2), and one Ni(3) atom to form a mixture of corner and edge-sharing OSrMgNi3 square pyramids. In the third O site, O(3) is bonded in a see-saw-like geometry to one Mg(1), one Ni(2), and two equivalent Ni(3) atoms. is represented by the CIF file [CIF]
data_SrMg(NiO2)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.380
_cell_length_b   6.330
_cell_length_c   6.380
_cell_angle_alpha   55.501
_cell_angle_beta   56.263
_cell_angle_gamma   55.501
_symmetry_Int_Tables_number   1
_cell_volume   164.222
_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
  Sr  Sr0  1  0.500  0.500  0.500  1.0
  Mg  Mg1  1  0.000  0.500  0.000  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  Ni  Ni3  1  0.500  0.000  0.500  1.0
  Ni  Ni4  1  0.500  0.500  0.000  1.0
  Ni  Ni5  1  0.000  0.500  0.500  1.0
  O  O6  1  0.767  0.293  0.767  1.0
  O  O7  1  0.205  0.264  0.735  1.0
  O  O8  1  0.233  0.707  0.233  1.0
  O  O9  1  0.735  0.264  0.205  1.0
  O  O10  1  0.258  0.293  0.258  1.0
  O  O11  1  0.742  0.707  0.742  1.0
  O  O12  1  0.795  0.736  0.265  1.0
  O  O13  1  0.265  0.736  0.795  1.0
[/CIF]
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