The structure described by Sr2Y2Ni2O7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. In the second Y site, Y(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form distorted YO4 trigonal pyramids that share corners with two equivalent Ni(1)O5 trigonal bipyramids and corners with two equivalent Y(2)O4 trigonal pyramids. Ni(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form NiO5 trigonal bipyramids that share corners with four equivalent Ni(1)O5 trigonal bipyramids and  a cornercorner with one Y(2)O4 trigonal pyramid. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 6-coordinate geometry to four equivalent Sr(1), one Y(2), and one Ni(1) atom. In the second O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Y(2) atoms. In the third O site, O(2) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form a mixture of distorted edge, corner, and face-sharing OSr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 2-70°. In the fourth O site, O(3) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form a mixture of distorted edge, corner, and face-sharing OSr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 3-70°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr2Y2Ni2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.627
_cell_length_b   12.627
_cell_length_c   12.627
_cell_angle_alpha   154.800
_cell_angle_beta   154.695
_cell_angle_gamma   36.014
_symmetry_Int_Tables_number   1
_cell_volume   365.946
_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
  Sr  Sr0  1  0.852  0.836  0.965  1.0
  Sr  Sr1  1  0.148  0.113  0.983  1.0
  Sr  Sr2  1  0.630  0.613  0.965  1.0
  Sr  Sr3  1  0.370  0.336  0.983  1.0
  Y  Y4  1  0.500  0.472  0.972  1.0
  Y  Y5  1  0.000  0.972  0.972  1.0
  Y  Y6  1  0.204  0.768  0.472  1.0
  Y  Y7  1  0.796  0.268  0.563  1.0
  Ni  Ni8  1  0.923  0.393  0.470  1.0
  Ni  Ni9  1  0.077  0.547  0.470  1.0
  Ni  Ni10  1  0.577  0.047  0.470  1.0
  Ni  Ni11  1  0.423  0.893  0.470  1.0
  O  O12  1  0.820  0.669  0.988  1.0
  O  O13  1  0.180  0.169  0.849  1.0
  O  O14  1  0.702  0.671  0.492  1.0
  O  O15  1  0.298  0.790  0.969  1.0
  O  O16  1  0.321  0.290  0.492  1.0
  O  O17  1  0.679  0.171  0.969  1.0
  O  O18  1  0.177  0.146  0.448  1.0
  O  O19  1  0.823  0.270  0.969  1.0
  O  O20  1  0.801  0.770  0.448  1.0
  O  O21  1  0.199  0.646  0.969  1.0
  O  O22  1  0.361  0.790  0.477  1.0
  O  O23  1  0.639  0.116  0.428  1.0
  O  O24  1  0.187  0.616  0.477  1.0
  O  O25  1  0.813  0.290  0.428  1.0
[/CIF]
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The structure described by Sr2Y2Ni2O7 crystallizes in the orthorhombic Ima2 space group. Sr(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and four equivalent O(4) atoms. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded in a body-centered cubic geometry to four equivalent O(2) and four equivalent O(3) atoms. In the second Y site, Y(2) is bonded to two equivalent O(1) and two equivalent O(4) atoms to form distorted YO4 trigonal pyramids that share corners with two equivalent Ni(1)O5 trigonal bipyramids and corners with two equivalent Y(2)O4 trigonal pyramids. Ni(1) is bonded to one O(4), two equivalent O(2), and two equivalent O(3) atoms to form NiO5 trigonal bipyramids that share corners with four equivalent Ni(1)O5 trigonal bipyramids and  a cornercorner with one Y(2)O4 trigonal pyramid. There are four inequivalent O sites. In the first O site, O(4) is bonded in a 6-coordinate geometry to four equivalent Sr(1), one Y(2), and one Ni(1) atom. In the second O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Sr(1) and two equivalent Y(2) atoms. In the third O site, O(2) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form a mixture of distorted edge, corner, and face-sharing OSr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 2-70°. In the fourth O site, O(3) is bonded to two equivalent Sr(1), two equivalent Y(1), and two equivalent Ni(1) atoms to form a mixture of distorted edge, corner, and face-sharing OSr2Y2Ni2 octahedra. The corner-sharing octahedral tilt angles range from 3-70°. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sr2Y2Ni2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   12.627
_cell_length_b   12.627
_cell_length_c   12.627
_cell_angle_alpha   154.800
_cell_angle_beta   154.695
_cell_angle_gamma   36.014
_symmetry_Int_Tables_number   1
_cell_volume   365.946
_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
  Sr  Sr0  1  0.852  0.836  0.965  1.0
  Sr  Sr1  1  0.148  0.113  0.983  1.0
  Sr  Sr2  1  0.630  0.613  0.965  1.0
  Sr  Sr3  1  0.370  0.336  0.983  1.0
  Y  Y4  1  0.500  0.472  0.972  1.0
  Y  Y5  1  0.000  0.972  0.972  1.0
  Y  Y6  1  0.204  0.768  0.472  1.0
  Y  Y7  1  0.796  0.268  0.563  1.0
  Ni  Ni8  1  0.923  0.393  0.470  1.0
  Ni  Ni9  1  0.077  0.547  0.470  1.0
  Ni  Ni10  1  0.577  0.047  0.470  1.0
  Ni  Ni11  1  0.423  0.893  0.470  1.0
  O  O12  1  0.820  0.669  0.988  1.0
  O  O13  1  0.180  0.169  0.849  1.0
  O  O14  1  0.702  0.671  0.492  1.0
  O  O15  1  0.298  0.790  0.969  1.0
  O  O16  1  0.321  0.290  0.492  1.0
  O  O17  1  0.679  0.171  0.969  1.0
  O  O18  1  0.177  0.146  0.448  1.0
  O  O19  1  0.823  0.270  0.969  1.0
  O  O20  1  0.801  0.770  0.448  1.0
  O  O21  1  0.199  0.646  0.969  1.0
  O  O22  1  0.361  0.790  0.477  1.0
  O  O23  1  0.639  0.116  0.428  1.0
  O  O24  1  0.187  0.616  0.477  1.0
  O  O25  1  0.813  0.290  0.428  1.0
[/CIF]
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