The structure described by MgNi2(PO4)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. There are two 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 distorted NiO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra and edges with two equivalent Ni(2)O6 octahedra. 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 P(1)O4 tetrahedra and edges with two equivalent Ni(1)O6 octahedra. P(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-59°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Ni(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Ni(1), one Ni(2), and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Ni(2) and one P(1) atom. is represented by the CIF file [CIF]
data_MgNi2(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.922
_cell_length_b   4.922
_cell_length_c   6.511
_cell_angle_alpha   87.321
_cell_angle_beta   87.321
_cell_angle_gamma   67.664
_symmetry_Int_Tables_number   1
_cell_volume   145.667
_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  0.500  0.500  1.0
  Ni  Ni1  1  0.000  0.000  0.500  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  P  P3  1  0.333  0.333  0.216  1.0
  P  P4  1  0.667  0.667  0.784  1.0
  O  O5  1  0.766  0.766  0.573  1.0
  O  O6  1  0.681  0.230  0.246  1.0
  O  O7  1  0.230  0.681  0.246  1.0
  O  O8  1  0.319  0.770  0.754  1.0
  O  O9  1  0.759  0.759  0.975  1.0
  O  O10  1  0.234  0.234  0.427  1.0
  O  O11  1  0.770  0.319  0.754  1.0
  O  O12  1  0.241  0.241  0.025  1.0
[/CIF]
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The structure described by MgNi2(PO4)2 crystallizes in the monoclinic C2/m space group. Mg(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. There are two 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 distorted NiO6 octahedra that share corners with six equivalent P(1)O4 tetrahedra and edges with two equivalent Ni(2)O6 octahedra. 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 P(1)O4 tetrahedra and edges with two equivalent Ni(1)O6 octahedra. P(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with three equivalent Ni(1)O6 octahedra and corners with three equivalent Ni(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-59°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1), one Ni(1), and one P(1) atom. In the second O site, O(2) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Ni(1), one Ni(2), and one P(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Ni(2) and one P(1) atom. is represented by the CIF file [CIF]
data_MgNi2(PO4)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.922
_cell_length_b   4.922
_cell_length_c   6.511
_cell_angle_alpha   87.321
_cell_angle_beta   87.321
_cell_angle_gamma   67.664
_symmetry_Int_Tables_number   1
_cell_volume   145.667
_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  0.500  0.500  1.0
  Ni  Ni1  1  0.000  0.000  0.500  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  P  P3  1  0.333  0.333  0.216  1.0
  P  P4  1  0.667  0.667  0.784  1.0
  O  O5  1  0.766  0.766  0.573  1.0
  O  O6  1  0.681  0.230  0.246  1.0
  O  O7  1  0.230  0.681  0.246  1.0
  O  O8  1  0.319  0.770  0.754  1.0
  O  O9  1  0.759  0.759  0.975  1.0
  O  O10  1  0.234  0.234  0.427  1.0
  O  O11  1  0.770  0.319  0.754  1.0
  O  O12  1  0.241  0.241  0.025  1.0
[/CIF]
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