The crystal structure described by MgNi2(BiO3)4 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(7), one O(9), and two equivalent O(1) atoms to form distorted MgO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Bi(4)O6 octahedra, corners with two equivalent Bi(3)O6 octahedra, and  an edgeedge with one Bi(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-53°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(2) atoms. In the second Ni site, Ni(2) is bonded to one O(5), one O(6), one O(7), one O(8), and two equivalent O(3) atoms to form NiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Bi(2)O5 trigonal bipyramids,  an edgeedge with one Bi(3)O6 octahedra, and  an edgeedge with one Bi(4)O6 octahedra. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(1), and two equivalent O(3) atoms. In the second Bi site, Bi(2) is bonded to one O(8), two equivalent O(2), and two equivalent O(3) atoms to form distorted BiO5 trigonal bipyramids that share corners with three equivalent Ni(2)O6 octahedra and corners with three equivalent Bi(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-58°. In the third Bi site, Bi(3) is bonded to one O(4), one O(5), one O(7), one O(9), and two equivalent O(1) atoms to form BiO6 octahedra that share corners with two equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Bi(4)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. In the fourth Bi site, Bi(4) is bonded to one O(4), one O(6), one O(8), one O(9), and two equivalent O(2) atoms to form BiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Bi(2)O5 trigonal bipyramids,  an edgeedge with one Ni(2)O6 octahedra, and  an edgeedge with one Bi(3)O6 octahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ni(1), one Bi(2), and one Bi(4) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ni(2), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ni(1), one Bi(3), and one Bi(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ni(2), one Bi(1), and one Bi(3) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one Ni(2) and one Bi(4) atom. In the seventh O site, O(7) is bonded in a T-shaped geometry to one Mg(1), one Ni(2), and one Bi(3) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Ni(2), one Bi(2), and one Bi(4) atom. In the ninth O site, O(9) is bonded in a T-shaped geometry to one Mg(1), one Bi(3), and one Bi(4) atom. is represented by the CIF file [CIF]
data_MgNi2(BiO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.514
_cell_length_b   5.514
_cell_length_c   9.669
_cell_angle_alpha   89.235
_cell_angle_beta   89.235
_cell_angle_gamma   76.859
_symmetry_Int_Tables_number   1
_cell_volume   286.296
_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  0.801  0.801  0.148  1.0
  Ni  Ni1  1  0.074  0.074  0.988  1.0
  Ni  Ni2  1  0.509  0.509  0.503  1.0
  Bi  Bi3  1  0.083  0.083  0.350  1.0
  Bi  Bi4  1  0.928  0.928  0.673  1.0
  Bi  Bi5  1  0.462  0.462  0.169  1.0
  Bi  Bi6  1  0.495  0.495  0.828  1.0
  O  O7  1  0.162  0.791  0.151  1.0
  O  O8  1  0.189  0.819  0.841  1.0
  O  O9  1  0.204  0.809  0.514  1.0
  O  O10  1  0.308  0.308  0.996  1.0
  O  O11  1  0.335  0.335  0.356  1.0
  O  O12  1  0.354  0.354  0.663  1.0
  O  O13  1  0.651  0.651  0.305  1.0
  O  O14  1  0.684  0.684  0.668  1.0
  O  O15  1  0.642  0.642  0.003  1.0
  O  O16  1  0.809  0.204  0.514  1.0
  O  O17  1  0.791  0.162  0.151  1.0
  O  O18  1  0.819  0.189  0.841  1.0
[/CIF]
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The crystal structure described by MgNi2(BiO3)4 crystallizes in the monoclinic Cm space group. Mg(1) is bonded to one O(7), one O(9), and two equivalent O(1) atoms to form distorted MgO4 tetrahedra that share  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Bi(4)O6 octahedra, corners with two equivalent Bi(3)O6 octahedra, and  an edgeedge with one Bi(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 8-53°. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(2) atoms. In the second Ni site, Ni(2) is bonded to one O(5), one O(6), one O(7), one O(8), and two equivalent O(3) atoms to form NiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Bi(2)O5 trigonal bipyramids,  an edgeedge with one Bi(3)O6 octahedra, and  an edgeedge with one Bi(4)O6 octahedra. There are four inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 5-coordinate geometry to one O(5), two equivalent O(1), and two equivalent O(3) atoms. In the second Bi site, Bi(2) is bonded to one O(8), two equivalent O(2), and two equivalent O(3) atoms to form distorted BiO5 trigonal bipyramids that share corners with three equivalent Ni(2)O6 octahedra and corners with three equivalent Bi(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 45-58°. In the third Bi site, Bi(3) is bonded to one O(4), one O(5), one O(7), one O(9), and two equivalent O(1) atoms to form BiO6 octahedra that share corners with two equivalent Mg(1)O4 tetrahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Bi(4)O6 octahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. In the fourth Bi site, Bi(4) is bonded to one O(4), one O(6), one O(8), one O(9), and two equivalent O(2) atoms to form BiO6 octahedra that share  a cornercorner with one Mg(1)O4 tetrahedra, corners with three equivalent Bi(2)O5 trigonal bipyramids,  an edgeedge with one Ni(2)O6 octahedra, and  an edgeedge with one Bi(3)O6 octahedra. There are nine inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Ni(1), one Bi(1), and one Bi(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Ni(1), one Bi(2), and one Bi(4) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Ni(2), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Ni(1), one Bi(3), and one Bi(4) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ni(2), one Bi(1), and one Bi(3) atom. In the sixth O site, O(6) is bonded in a water-like geometry to one Ni(2) and one Bi(4) atom. In the seventh O site, O(7) is bonded in a T-shaped geometry to one Mg(1), one Ni(2), and one Bi(3) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one Ni(2), one Bi(2), and one Bi(4) atom. In the ninth O site, O(9) is bonded in a T-shaped geometry to one Mg(1), one Bi(3), and one Bi(4) atom. is represented by the CIF file [CIF]
data_MgNi2(BiO3)4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.514
_cell_length_b   5.514
_cell_length_c   9.669
_cell_angle_alpha   89.235
_cell_angle_beta   89.235
_cell_angle_gamma   76.859
_symmetry_Int_Tables_number   1
_cell_volume   286.296
_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  0.801  0.801  0.148  1.0
  Ni  Ni1  1  0.074  0.074  0.988  1.0
  Ni  Ni2  1  0.509  0.509  0.503  1.0
  Bi  Bi3  1  0.083  0.083  0.350  1.0
  Bi  Bi4  1  0.928  0.928  0.673  1.0
  Bi  Bi5  1  0.462  0.462  0.169  1.0
  Bi  Bi6  1  0.495  0.495  0.828  1.0
  O  O7  1  0.162  0.791  0.151  1.0
  O  O8  1  0.189  0.819  0.841  1.0
  O  O9  1  0.204  0.809  0.514  1.0
  O  O10  1  0.308  0.308  0.996  1.0
  O  O11  1  0.335  0.335  0.356  1.0
  O  O12  1  0.354  0.354  0.663  1.0
  O  O13  1  0.651  0.651  0.305  1.0
  O  O14  1  0.684  0.684  0.668  1.0
  O  O15  1  0.642  0.642  0.003  1.0
  O  O16  1  0.809  0.204  0.514  1.0
  O  O17  1  0.791  0.162  0.151  1.0
  O  O18  1  0.819  0.189  0.841  1.0
[/CIF]
.