The structure described by NiNb2O6 crystallizes in the monoclinic C2/m space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. In the third Nb site, Nb(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. Ni(1) is bonded in a 3-coordinate geometry to one O(3) and two equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Nb(1) and two equivalent Nb(3) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nb(3), one Ni(1), and one O(5) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Nb(2), one Nb(3), and one Ni(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Nb(3) and one O(3) atom. is represented by the CIF file [CIF]
data_Nb2NiO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.650
_cell_length_b   5.650
_cell_length_c   6.776
_cell_angle_alpha   88.357
_cell_angle_beta   88.357
_cell_angle_gamma   71.382
_symmetry_Int_Tables_number   1
_cell_volume   204.860
_cell_formula_units_Z   2
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
  Nb  Nb0  1  0.000  0.000  0.500  1.0
  Nb  Nb1  1  0.000  0.000  0.000  1.0
  Nb  Nb2  1  0.388  0.388  0.284  1.0
  Nb  Nb3  1  0.612  0.612  0.716  1.0
  Ni  Ni4  1  0.244  0.244  0.659  1.0
  Ni  Ni5  1  0.756  0.756  0.341  1.0
  O  O6  1  0.839  0.839  0.732  1.0
  O  O7  1  0.686  0.314  0.500  1.0
  O  O8  1  0.314  0.686  0.500  1.0
  O  O9  1  0.161  0.161  0.268  1.0
  O  O10  1  0.409  0.409  0.828  1.0
  O  O11  1  0.713  0.093  0.192  1.0
  O  O12  1  0.093  0.713  0.192  1.0
  O  O13  1  0.678  0.678  0.998  1.0
  O  O14  1  0.322  0.322  0.002  1.0
  O  O15  1  0.287  0.907  0.808  1.0
  O  O16  1  0.907  0.287  0.808  1.0
  O  O17  1  0.591  0.591  0.172  1.0
[/CIF]
.
The structure described by NiNb2O6 crystallizes in the monoclinic C2/m space group. There are three inequivalent Nb sites. In the first Nb site, Nb(1) is bonded in a distorted square co-planar geometry to two equivalent O(1) and two equivalent O(2) atoms. In the second Nb site, Nb(2) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. In the third Nb site, Nb(3) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(5), two equivalent O(2), and two equivalent O(4) atoms. Ni(1) is bonded in a 3-coordinate geometry to one O(3) and two equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Nb(1), one Nb(2), and one Nb(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Nb(1) and two equivalent Nb(3) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Nb(3), one Ni(1), and one O(5) atom. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Nb(2), one Nb(3), and one Ni(1) atom. In the fifth O site, O(5) is bonded in a 2-coordinate geometry to one Nb(3) and one O(3) atom. is represented by the CIF file [CIF]
data_Nb2NiO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.650
_cell_length_b   5.650
_cell_length_c   6.776
_cell_angle_alpha   88.357
_cell_angle_beta   88.357
_cell_angle_gamma   71.382
_symmetry_Int_Tables_number   1
_cell_volume   204.860
_cell_formula_units_Z   2
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
  Nb  Nb0  1  0.000  0.000  0.500  1.0
  Nb  Nb1  1  0.000  0.000  0.000  1.0
  Nb  Nb2  1  0.388  0.388  0.284  1.0
  Nb  Nb3  1  0.612  0.612  0.716  1.0
  Ni  Ni4  1  0.244  0.244  0.659  1.0
  Ni  Ni5  1  0.756  0.756  0.341  1.0
  O  O6  1  0.839  0.839  0.732  1.0
  O  O7  1  0.686  0.314  0.500  1.0
  O  O8  1  0.314  0.686  0.500  1.0
  O  O9  1  0.161  0.161  0.268  1.0
  O  O10  1  0.409  0.409  0.828  1.0
  O  O11  1  0.713  0.093  0.192  1.0
  O  O12  1  0.093  0.713  0.192  1.0
  O  O13  1  0.678  0.678  0.998  1.0
  O  O14  1  0.322  0.322  0.002  1.0
  O  O15  1  0.287  0.907  0.808  1.0
  O  O16  1  0.907  0.287  0.808  1.0
  O  O17  1  0.591  0.591  0.172  1.0
[/CIF]
.