The crystal structure described by Ca2Ni2O5 crystallizes in the orthorhombic Pbam space group. Ca(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. Ni(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Ni(1) atoms to form edge-sharing OCa4Ni2 octahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Ni2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.786
_cell_length_b   5.350
_cell_length_c   10.314
_cell_angle_alpha   90.003
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   208.910
_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
  Ca  Ca0  1  0.500  0.195  0.871  1.0
  Ca  Ca1  1  0.500  0.805  0.129  1.0
  Ca  Ca2  1  0.500  0.695  0.630  1.0
  Ca  Ca3  1  0.500  0.305  0.370  1.0
  Ni  Ni4  1  1.000  0.229  0.626  1.0
  Ni  Ni5  1  0.000  0.771  0.374  1.0
  Ni  Ni6  1  0.000  0.271  0.126  1.0
  Ni  Ni7  1  0.000  0.729  0.874  1.0
  O  O8  1  0.000  0.500  0.500  1.0
  O  O9  1  0.000  0.080  0.288  1.0
  O  O10  1  0.000  0.580  0.212  1.0
  O  O11  1  0.000  0.420  0.788  1.0
  O  O12  1  0.500  0.290  0.101  1.0
  O  O13  1  0.500  0.710  0.899  1.0
  O  O14  1  0.000  0.920  0.712  1.0
  O  O15  1  0.500  0.210  0.601  1.0
  O  O16  1  0.000  0.000  1.000  1.0
  O  O17  1  0.500  0.790  0.399  1.0
[/CIF]
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The crystal structure described by Ca2Ni2O5 crystallizes in the orthorhombic Pbam space group. Ca(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. Ni(1) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing NiO5 square pyramids. There are three inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) and two equivalent Ni(1) atoms to form edge-sharing OCa4Ni2 octahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms. In the third O site, O(3) is bonded in a 6-coordinate geometry to four equivalent Ca(1) and two equivalent Ni(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Ni2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.786
_cell_length_b   5.350
_cell_length_c   10.314
_cell_angle_alpha   90.003
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   208.910
_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
  Ca  Ca0  1  0.500  0.195  0.871  1.0
  Ca  Ca1  1  0.500  0.805  0.129  1.0
  Ca  Ca2  1  0.500  0.695  0.630  1.0
  Ca  Ca3  1  0.500  0.305  0.370  1.0
  Ni  Ni4  1  1.000  0.229  0.626  1.0
  Ni  Ni5  1  0.000  0.771  0.374  1.0
  Ni  Ni6  1  0.000  0.271  0.126  1.0
  Ni  Ni7  1  0.000  0.729  0.874  1.0
  O  O8  1  0.000  0.500  0.500  1.0
  O  O9  1  0.000  0.080  0.288  1.0
  O  O10  1  0.000  0.580  0.212  1.0
  O  O11  1  0.000  0.420  0.788  1.0
  O  O12  1  0.500  0.290  0.101  1.0
  O  O13  1  0.500  0.710  0.899  1.0
  O  O14  1  0.000  0.920  0.712  1.0
  O  O15  1  0.500  0.210  0.601  1.0
  O  O16  1  0.000  0.000  1.000  1.0
  O  O17  1  0.500  0.790  0.399  1.0
[/CIF]
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