The crystal structure described by La2NiO4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. La(1) is bonded in a 9-coordinate geometry to four equivalent O(2) and five equivalent O(1) atoms. Ni(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form corner-sharing NiO6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent La(1) and two equivalent Ni(1) atoms to form OLa4Ni2 octahedra that share corners with two equivalent O(2)La4Ni2 octahedra, corners with twelve equivalent O(1)La5Ni octahedra, edges with two equivalent O(2)La4Ni2 octahedra, faces with four equivalent O(2)La4Ni2 octahedra, and faces with four equivalent O(1)La5Ni octahedra. The corner-sharing octahedral tilt angles range from 0-50°. In the second O site, O(1) is bonded to five equivalent La(1) and one Ni(1) atom to form distorted OLa5Ni octahedra that share corners with five equivalent O(1)La5Ni octahedra, corners with twelve equivalent O(2)La4Ni2 octahedra, edges with eight equivalent O(1)La5Ni octahedra, and faces with four equivalent O(2)La4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-50°. is represented by the Crystallographic Information File (CIF) [CIF]
data_La2NiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.924
_cell_length_b   3.924
_cell_length_c   6.848
_cell_angle_alpha   106.650
_cell_angle_beta   106.650
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   96.397
_cell_formula_units_Z   1
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
  La  La0  1  0.363  0.363  0.727  1.0
  La  La1  1  0.637  0.637  0.273  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  O  O3  1  0.179  0.179  0.358  1.0
  O  O4  1  0.821  0.821  0.642  1.0
  O  O5  1  0.500  0.000  0.000  1.0
  O  O6  1  0.000  0.500  0.000  1.0
[/CIF]
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The crystal structure described by La2NiO4 is (La,Ba)CuO4 structured and crystallizes in the tetragonal I4/mmm space group. La(1) is bonded in a 9-coordinate geometry to four equivalent O(2) and five equivalent O(1) atoms. Ni(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form corner-sharing NiO6 octahedra. The corner-sharing octahedra are not tilted. There are two inequivalent O sites. In the first O site, O(2) is bonded to four equivalent La(1) and two equivalent Ni(1) atoms to form OLa4Ni2 octahedra that share corners with two equivalent O(2)La4Ni2 octahedra, corners with twelve equivalent O(1)La5Ni octahedra, edges with two equivalent O(2)La4Ni2 octahedra, faces with four equivalent O(2)La4Ni2 octahedra, and faces with four equivalent O(1)La5Ni octahedra. The corner-sharing octahedral tilt angles range from 0-50°. In the second O site, O(1) is bonded to five equivalent La(1) and one Ni(1) atom to form distorted OLa5Ni octahedra that share corners with five equivalent O(1)La5Ni octahedra, corners with twelve equivalent O(2)La4Ni2 octahedra, edges with eight equivalent O(1)La5Ni octahedra, and faces with four equivalent O(2)La4Ni2 octahedra. The corner-sharing octahedral tilt angles range from 0-50°. is represented by the Crystallographic Information File (CIF) [CIF]
data_La2NiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.924
_cell_length_b   3.924
_cell_length_c   6.848
_cell_angle_alpha   106.650
_cell_angle_beta   106.650
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   96.397
_cell_formula_units_Z   1
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
  La  La0  1  0.363  0.363  0.727  1.0
  La  La1  1  0.637  0.637  0.273  1.0
  Ni  Ni2  1  0.000  0.000  0.000  1.0
  O  O3  1  0.179  0.179  0.358  1.0
  O  O4  1  0.821  0.821  0.642  1.0
  O  O5  1  0.500  0.000  0.000  1.0
  O  O6  1  0.000  0.500  0.000  1.0
[/CIF]
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