The structure described by VNiP2O9 crystallizes in the orthorhombic Pnma space group. V(1) is bonded to one O(3), one O(4), one O(6), one O(7), and two equivalent O(5) atoms to form distorted VO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent V(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(7), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with three equivalent V(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-51°. In the second P site, P(2) is bonded to one O(4), one O(6), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and  an edgeedge with one V(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are seven inequivalent O sites. In the first O site, O(4) is bonded in a water-like geometry to one V(1) and one P(2) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one V(1) and one P(1) atom. In the third O site, O(6) is bonded in an L-shaped geometry to one V(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a bent 120 degrees geometry to one Ni(1) and one P(2) atom. In the fifth O site, O(7) is bonded in a linear geometry to one V(1) and one P(1) atom. In the sixth O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ni(1) and one P(1) atom. In the seventh O site, O(3) is bonded in a 3-coordinate geometry to one V(1) and two equivalent Ni(1) atoms. is represented by the CIF file [CIF]
data_VNiP2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.276
_cell_length_b   7.817
_cell_length_c   13.928
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   683.346
_cell_formula_units_Z   4
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
  V  V0  1  0.750  0.845  0.381  1.0
  V  V1  1  0.250  0.155  0.619  1.0
  V  V2  1  0.250  0.345  0.119  1.0
  V  V3  1  0.750  0.655  0.881  1.0
  Ni  Ni4  1  0.500  0.500  0.500  1.0
  Ni  Ni5  1  0.500  0.000  0.000  1.0
  Ni  Ni6  1  0.000  0.000  0.000  1.0
  Ni  Ni7  1  0.000  0.500  0.500  1.0
  P  P8  1  0.250  0.849  0.440  1.0
  P  P9  1  0.750  0.151  0.560  1.0
  P  P10  1  0.750  0.349  0.060  1.0
  P  P11  1  0.250  0.651  0.940  1.0
  P  P12  1  0.750  0.890  0.190  1.0
  P  P13  1  0.250  0.110  0.810  1.0
  P  P14  1  0.250  0.390  0.310  1.0
  P  P15  1  0.750  0.610  0.690  1.0
  O  O16  1  0.048  0.107  0.872  1.0
  O  O17  1  0.548  0.893  0.128  1.0
  O  O18  1  0.952  0.607  0.628  1.0
  O  O19  1  0.452  0.393  0.372  1.0
  O  O20  1  0.952  0.893  0.128  1.0
  O  O21  1  0.452  0.107  0.872  1.0
  O  O22  1  0.048  0.393  0.372  1.0
  O  O23  1  0.548  0.607  0.628  1.0
  O  O24  1  0.250  0.834  0.981  1.0
  O  O25  1  0.750  0.166  0.019  1.0
  O  O26  1  0.750  0.334  0.519  1.0
  O  O27  1  0.250  0.666  0.481  1.0
  O  O28  1  0.750  0.659  0.444  1.0
  O  O29  1  0.250  0.341  0.556  1.0
  O  O30  1  0.250  0.159  0.056  1.0
  O  O31  1  0.750  0.841  0.944  1.0
  O  O32  1  0.750  0.729  0.259  1.0
  O  O33  1  0.250  0.271  0.741  1.0
  O  O34  1  0.250  0.229  0.241  1.0
  O  O35  1  0.750  0.771  0.759  1.0
  O  O36  1  0.449  0.628  0.876  1.0
  O  O37  1  0.949  0.372  0.124  1.0
  O  O38  1  0.551  0.128  0.624  1.0
  O  O39  1  0.051  0.872  0.376  1.0
  O  O40  1  0.551  0.372  0.124  1.0
  O  O41  1  0.051  0.628  0.876  1.0
  O  O42  1  0.449  0.872  0.376  1.0
  O  O43  1  0.949  0.128  0.624  1.0
  O  O44  1  0.750  0.467  0.768  1.0
  O  O45  1  0.250  0.533  0.232  1.0
  O  O46  1  0.250  0.967  0.732  1.0
  O  O47  1  0.750  0.033  0.268  1.0
  O  O48  1  0.750  0.487  0.981  1.0
  O  O49  1  0.250  0.513  0.019  1.0
  O  O50  1  0.250  0.987  0.519  1.0
  O  O51  1  0.750  0.013  0.481  1.0
[/CIF]
.
The structure described by VNiP2O9 crystallizes in the orthorhombic Pnma space group. V(1) is bonded to one O(3), one O(4), one O(6), one O(7), and two equivalent O(5) atoms to form distorted VO6 octahedra that share corners with two equivalent Ni(1)O6 octahedra, corners with three equivalent P(1)O4 tetrahedra, and  an edgeedge with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 47°. Ni(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NiO6 octahedra that share corners with two equivalent V(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and edges with two equivalent Ni(1)O6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(2), one O(7), and two equivalent O(5) atoms to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and corners with three equivalent V(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-51°. In the second P site, P(2) is bonded to one O(4), one O(6), and two equivalent O(1) atoms to form PO4 tetrahedra that share corners with two equivalent Ni(1)O6 octahedra and  an edgeedge with one V(1)O6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are seven inequivalent O sites. In the first O site, O(4) is bonded in a water-like geometry to one V(1) and one P(2) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one V(1) and one P(1) atom. In the third O site, O(6) is bonded in an L-shaped geometry to one V(1) and one P(2) atom. In the fourth O site, O(1) is bonded in a bent 120 degrees geometry to one Ni(1) and one P(2) atom. In the fifth O site, O(7) is bonded in a linear geometry to one V(1) and one P(1) atom. In the sixth O site, O(2) is bonded in a distorted trigonal planar geometry to two equivalent Ni(1) and one P(1) atom. In the seventh O site, O(3) is bonded in a 3-coordinate geometry to one V(1) and two equivalent Ni(1) atoms. is represented by the CIF file [CIF]
data_VNiP2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.276
_cell_length_b   7.817
_cell_length_c   13.928
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   683.346
_cell_formula_units_Z   4
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
  V  V0  1  0.750  0.845  0.381  1.0
  V  V1  1  0.250  0.155  0.619  1.0
  V  V2  1  0.250  0.345  0.119  1.0
  V  V3  1  0.750  0.655  0.881  1.0
  Ni  Ni4  1  0.500  0.500  0.500  1.0
  Ni  Ni5  1  0.500  0.000  0.000  1.0
  Ni  Ni6  1  0.000  0.000  0.000  1.0
  Ni  Ni7  1  0.000  0.500  0.500  1.0
  P  P8  1  0.250  0.849  0.440  1.0
  P  P9  1  0.750  0.151  0.560  1.0
  P  P10  1  0.750  0.349  0.060  1.0
  P  P11  1  0.250  0.651  0.940  1.0
  P  P12  1  0.750  0.890  0.190  1.0
  P  P13  1  0.250  0.110  0.810  1.0
  P  P14  1  0.250  0.390  0.310  1.0
  P  P15  1  0.750  0.610  0.690  1.0
  O  O16  1  0.048  0.107  0.872  1.0
  O  O17  1  0.548  0.893  0.128  1.0
  O  O18  1  0.952  0.607  0.628  1.0
  O  O19  1  0.452  0.393  0.372  1.0
  O  O20  1  0.952  0.893  0.128  1.0
  O  O21  1  0.452  0.107  0.872  1.0
  O  O22  1  0.048  0.393  0.372  1.0
  O  O23  1  0.548  0.607  0.628  1.0
  O  O24  1  0.250  0.834  0.981  1.0
  O  O25  1  0.750  0.166  0.019  1.0
  O  O26  1  0.750  0.334  0.519  1.0
  O  O27  1  0.250  0.666  0.481  1.0
  O  O28  1  0.750  0.659  0.444  1.0
  O  O29  1  0.250  0.341  0.556  1.0
  O  O30  1  0.250  0.159  0.056  1.0
  O  O31  1  0.750  0.841  0.944  1.0
  O  O32  1  0.750  0.729  0.259  1.0
  O  O33  1  0.250  0.271  0.741  1.0
  O  O34  1  0.250  0.229  0.241  1.0
  O  O35  1  0.750  0.771  0.759  1.0
  O  O36  1  0.449  0.628  0.876  1.0
  O  O37  1  0.949  0.372  0.124  1.0
  O  O38  1  0.551  0.128  0.624  1.0
  O  O39  1  0.051  0.872  0.376  1.0
  O  O40  1  0.551  0.372  0.124  1.0
  O  O41  1  0.051  0.628  0.876  1.0
  O  O42  1  0.449  0.872  0.376  1.0
  O  O43  1  0.949  0.128  0.624  1.0
  O  O44  1  0.750  0.467  0.768  1.0
  O  O45  1  0.250  0.533  0.232  1.0
  O  O46  1  0.250  0.967  0.732  1.0
  O  O47  1  0.750  0.033  0.268  1.0
  O  O48  1  0.750  0.487  0.981  1.0
  O  O49  1  0.250  0.513  0.019  1.0
  O  O50  1  0.250  0.987  0.519  1.0
  O  O51  1  0.750  0.013  0.481  1.0
[/CIF]
.