The compound described by Li2NiP2O7 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted see-saw-like geometry to one O(2), one O(3), one O(4), and one O(5) atom. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(6) atom. Ni(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form NiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share 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 48-49°. In the second P site, P(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form PO4 tetrahedra that share 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 26-52°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Ni(1), and one P(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Ni(1), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Ni(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), one Li(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(2), one Ni(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one P(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2NiP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.997
_cell_length_b   7.112
_cell_length_c   8.280
_cell_angle_alpha   89.999
_cell_angle_beta   89.999
_cell_angle_gamma   70.870
_symmetry_Int_Tables_number   1
_cell_volume   278.003
_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
  Li  Li0  1  0.170  0.349  0.145  1.0
  Li  Li1  1  0.830  0.651  0.645  1.0
  Li  Li2  1  0.657  0.084  0.320  1.0
  Li  Li3  1  0.343  0.916  0.820  1.0
  Ni  Ni4  1  0.203  0.279  0.504  1.0
  Ni  Ni5  1  0.797  0.721  0.004  1.0
  O  O6  1  0.072  0.116  0.681  1.0
  O  O7  1  0.928  0.884  0.181  1.0
  O  O8  1  0.178  0.108  0.299  1.0
  O  O9  1  0.822  0.892  0.799  1.0
  O  O10  1  0.196  0.515  0.962  1.0
  O  O11  1  0.804  0.485  0.462  1.0
  O  O12  1  0.229  0.496  0.656  1.0
  O  O13  1  0.771  0.504  0.156  1.0
  O  O14  1  0.431  0.378  0.312  1.0
  O  O15  1  0.569  0.622  0.812  1.0
  O  O16  1  0.614  0.096  0.553  1.0
  O  O17  1  0.386  0.904  0.053  1.0
  O  O18  1  0.603  0.256  0.834  1.0
  O  O19  1  0.397  0.744  0.334  1.0
  P  P20  1  0.389  0.483  0.815  1.0
  P  P21  1  0.611  0.517  0.315  1.0
  P  P22  1  0.215  0.913  0.208  1.0
  P  P23  1  0.785  0.087  0.708  1.0
[/CIF]
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The compound described by Li2NiP2O7 crystallizes in the monoclinic P2_1 space group. There are two inequivalent Li sites. In the first Li site, Li(1) is bonded in a distorted see-saw-like geometry to one O(2), one O(3), one O(4), and one O(5) atom. In the second Li site, Li(2) is bonded in a 4-coordinate geometry to one O(1), one O(2), one O(5), and one O(6) atom. Ni(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form NiO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), one O(5), and one O(7) atom to form PO4 tetrahedra that share 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 48-49°. In the second P site, P(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form PO4 tetrahedra that share 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 26-52°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Li(2), one Ni(1), and one P(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Li(1), one Li(2), one Ni(1), and one P(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Li(1), one Ni(1), and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Li(1), one Ni(1), and one P(1) atom. In the fifth O site, O(5) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), one Li(2), one Ni(1), and one P(1) atom. In the sixth O site, O(6) is bonded in a 3-coordinate geometry to one Li(2), one Ni(1), and one P(2) atom. In the seventh O site, O(7) is bonded in a distorted bent 120 degrees geometry to one P(1) and one P(2) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Li2NiP2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.997
_cell_length_b   7.112
_cell_length_c   8.280
_cell_angle_alpha   89.999
_cell_angle_beta   89.999
_cell_angle_gamma   70.870
_symmetry_Int_Tables_number   1
_cell_volume   278.003
_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
  Li  Li0  1  0.170  0.349  0.145  1.0
  Li  Li1  1  0.830  0.651  0.645  1.0
  Li  Li2  1  0.657  0.084  0.320  1.0
  Li  Li3  1  0.343  0.916  0.820  1.0
  Ni  Ni4  1  0.203  0.279  0.504  1.0
  Ni  Ni5  1  0.797  0.721  0.004  1.0
  O  O6  1  0.072  0.116  0.681  1.0
  O  O7  1  0.928  0.884  0.181  1.0
  O  O8  1  0.178  0.108  0.299  1.0
  O  O9  1  0.822  0.892  0.799  1.0
  O  O10  1  0.196  0.515  0.962  1.0
  O  O11  1  0.804  0.485  0.462  1.0
  O  O12  1  0.229  0.496  0.656  1.0
  O  O13  1  0.771  0.504  0.156  1.0
  O  O14  1  0.431  0.378  0.312  1.0
  O  O15  1  0.569  0.622  0.812  1.0
  O  O16  1  0.614  0.096  0.553  1.0
  O  O17  1  0.386  0.904  0.053  1.0
  O  O18  1  0.603  0.256  0.834  1.0
  O  O19  1  0.397  0.744  0.334  1.0
  P  P20  1  0.389  0.483  0.815  1.0
  P  P21  1  0.611  0.517  0.315  1.0
  P  P22  1  0.215  0.913  0.208  1.0
  P  P23  1  0.785  0.087  0.708  1.0
[/CIF]
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