The structure described by MgNiP2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MgO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with three equivalent Ni(1)O6 octahedra. Ni(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted NiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with three equivalent Mg(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-63°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-63°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Ni(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a linear geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Ni(1), and one P(2) atom. is represented by the CIF file [CIF]
data_MgNiP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.315
_cell_length_b   5.281
_cell_length_c   4.534
_cell_angle_alpha   81.773
_cell_angle_beta   98.193
_cell_angle_gamma   75.795
_symmetry_Int_Tables_number   1
_cell_volume   119.978
_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  0.758  0.765  0.005  1.0
  Ni  Ni1  1  0.135  0.136  0.001  1.0
  P  P2  1  0.236  0.674  0.594  1.0
  P  P3  1  0.673  0.236  0.407  1.0
  O  O4  1  0.827  0.070  0.716  1.0
  O  O5  1  0.084  0.517  0.776  1.0
  O  O6  1  0.838  0.372  0.218  1.0
  O  O7  1  0.371  0.841  0.783  1.0
  O  O8  1  0.475  0.478  0.497  1.0
  O  O9  1  0.068  0.829  0.287  1.0
  O  O10  1  0.520  0.080  0.227  1.0
[/CIF]
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The structure described by MgNiP2O7 crystallizes in the triclinic P1 space group. Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted MgO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with three equivalent Ni(1)O6 octahedra. Ni(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(6), and one O(7) atom to form distorted NiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra, corners with three equivalent P(2)O4 tetrahedra, and edges with three equivalent Mg(1)O6 octahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(4), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 41-63°. In the second P site, P(2) is bonded to one O(1), one O(3), one O(5), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Ni(1)O6 octahedra, and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 42-63°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(2) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to one Mg(1), one Ni(1), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a linear geometry to one P(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Mg(1), one Ni(1), and one P(1) atom. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(1), one Ni(1), and one P(2) atom. is represented by the CIF file [CIF]
data_MgNiP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.315
_cell_length_b   5.281
_cell_length_c   4.534
_cell_angle_alpha   81.773
_cell_angle_beta   98.193
_cell_angle_gamma   75.795
_symmetry_Int_Tables_number   1
_cell_volume   119.978
_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  0.758  0.765  0.005  1.0
  Ni  Ni1  1  0.135  0.136  0.001  1.0
  P  P2  1  0.236  0.674  0.594  1.0
  P  P3  1  0.673  0.236  0.407  1.0
  O  O4  1  0.827  0.070  0.716  1.0
  O  O5  1  0.084  0.517  0.776  1.0
  O  O6  1  0.838  0.372  0.218  1.0
  O  O7  1  0.371  0.841  0.783  1.0
  O  O8  1  0.475  0.478  0.497  1.0
  O  O9  1  0.068  0.829  0.287  1.0
  O  O10  1  0.520  0.080  0.227  1.0
[/CIF]
.