The compound described by Mg2Ni2O5 crystallizes in the orthorhombic Pbam space group. Mg(1) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(2), and three 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 Mg(1) and two equivalent Ni(1) atoms to form OMg4Ni2 octahedra that share corners with eight equivalent O(2)Mg2Ni2 tetrahedra, edges with two equivalent O(1)Mg4Ni2 octahedra, and edges with two equivalent O(2)Mg2Ni2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Ni(1) atoms to form OMg2Ni2 tetrahedra that share corners with four equivalent O(1)Mg4Ni2 octahedra, corners with four equivalent O(2)Mg2Ni2 tetrahedra, and  an edgeedge with one O(1)Mg4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 19-61°. In the third O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Mg(1) and two equivalent Ni(1) atoms. is represented by the CIF card [CIF]
data_Mg2Ni2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.731
_cell_length_b   4.926
_cell_length_c   10.297
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   189.231
_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
  Mg  Mg0  1  0.000  0.247  0.903  1.0
  Mg  Mg1  1  0.000  0.753  0.097  1.0
  Mg  Mg2  1  0.000  0.747  0.597  1.0
  Mg  Mg3  1  0.000  0.253  0.403  1.0
  Ni  Ni4  1  0.500  0.217  0.638  1.0
  Ni  Ni5  1  0.500  0.783  0.362  1.0
  Ni  Ni6  1  0.500  0.283  0.138  1.0
  Ni  Ni7  1  0.500  0.717  0.862  1.0
  O  O8  1  0.500  0.500  0.500  1.0
  O  O9  1  0.500  0.169  0.321  1.0
  O  O10  1  0.500  0.669  0.179  1.0
  O  O11  1  0.500  0.331  0.821  1.0
  O  O12  1  0.000  0.306  0.103  1.0
  O  O13  1  0.000  0.694  0.897  1.0
  O  O14  1  0.500  0.831  0.679  1.0
  O  O15  1  0.000  0.194  0.603  1.0
  O  O16  1  0.500  0.000  0.000  1.0
  O  O17  1  0.000  0.806  0.397  1.0
[/CIF]
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The compound described by Mg2Ni2O5 crystallizes in the orthorhombic Pbam space group. Mg(1) is bonded in a 7-coordinate geometry to two equivalent O(1), two equivalent O(2), and three 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 Mg(1) and two equivalent Ni(1) atoms to form OMg4Ni2 octahedra that share corners with eight equivalent O(2)Mg2Ni2 tetrahedra, edges with two equivalent O(1)Mg4Ni2 octahedra, and edges with two equivalent O(2)Mg2Ni2 tetrahedra. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Ni(1) atoms to form OMg2Ni2 tetrahedra that share corners with four equivalent O(1)Mg4Ni2 octahedra, corners with four equivalent O(2)Mg2Ni2 tetrahedra, and  an edgeedge with one O(1)Mg4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 19-61°. In the third O site, O(3) is bonded in a 4-coordinate geometry to three equivalent Mg(1) and two equivalent Ni(1) atoms. is represented by the CIF card [CIF]
data_Mg2Ni2O5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.731
_cell_length_b   4.926
_cell_length_c   10.297
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   189.231
_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
  Mg  Mg0  1  0.000  0.247  0.903  1.0
  Mg  Mg1  1  0.000  0.753  0.097  1.0
  Mg  Mg2  1  0.000  0.747  0.597  1.0
  Mg  Mg3  1  0.000  0.253  0.403  1.0
  Ni  Ni4  1  0.500  0.217  0.638  1.0
  Ni  Ni5  1  0.500  0.783  0.362  1.0
  Ni  Ni6  1  0.500  0.283  0.138  1.0
  Ni  Ni7  1  0.500  0.717  0.862  1.0
  O  O8  1  0.500  0.500  0.500  1.0
  O  O9  1  0.500  0.169  0.321  1.0
  O  O10  1  0.500  0.669  0.179  1.0
  O  O11  1  0.500  0.331  0.821  1.0
  O  O12  1  0.000  0.306  0.103  1.0
  O  O13  1  0.000  0.694  0.897  1.0
  O  O14  1  0.500  0.831  0.679  1.0
  O  O15  1  0.000  0.194  0.603  1.0
  O  O16  1  0.500  0.000  0.000  1.0
  O  O17  1  0.000  0.806  0.397  1.0
[/CIF]
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