The crystal structure described by La2NiO4 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one O(1), one O(4), three equivalent O(2), and three equivalent O(3) atoms. In the second La site, La(2) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. Ni(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form corner-sharing NiO5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one La(1), four equivalent La(2), and one Ni(1) atom. In the second O site, O(2) is bonded to one La(2), three equivalent La(1), and one Ni(1) atom to form OLa4Ni trigonal bipyramids that share  a cornercorner with one O(4)La3Ni2 square pyramid, corners with six equivalent O(2)La4Ni trigonal bipyramids, and edges with three equivalent O(4)La3Ni2 square pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent La(2), three equivalent La(1), and one Ni(1) atom. In the fourth O site, O(4) is bonded to one La(1), two equivalent La(2), and two equivalent Ni(1) atoms to form distorted OLa3Ni2 square pyramids that share corners with four equivalent O(4)La3Ni2 square pyramids,  a cornercorner with one O(2)La4Ni trigonal bipyramid, and edges with three equivalent O(2)La4Ni trigonal bipyramids. is represented by the CIF file [CIF]
data_La2NiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.077
_cell_length_b   7.077
_cell_length_c   7.343
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   147.463
_symmetry_Int_Tables_number   1
_cell_volume   197.832
_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
  La  La0  1  0.284  0.716  0.144  1.0
  La  La1  1  0.716  0.284  0.644  1.0
  La  La2  1  0.053  0.947  0.348  1.0
  La  La3  1  0.947  0.053  0.848  1.0
  Ni  Ni4  1  0.610  0.390  0.037  1.0
  Ni  Ni5  1  0.390  0.610  0.537  1.0
  O  O6  1  0.543  0.457  0.636  1.0
  O  O7  1  0.766  0.234  0.983  1.0
  O  O8  1  0.353  0.647  0.793  1.0
  O  O9  1  0.234  0.766  0.483  1.0
  O  O10  1  0.647  0.353  0.293  1.0
  O  O11  1  0.898  0.102  0.496  1.0
  O  O12  1  0.457  0.543  0.136  1.0
  O  O13  1  0.102  0.898  0.996  1.0
[/CIF]
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The crystal structure described by La2NiO4 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one O(1), one O(4), three equivalent O(2), and three equivalent O(3) atoms. In the second La site, La(2) is bonded in a 9-coordinate geometry to one O(2), two equivalent O(3), two equivalent O(4), and four equivalent O(1) atoms. Ni(1) is bonded to one O(1), one O(2), one O(3), and two equivalent O(4) atoms to form corner-sharing NiO5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to one La(1), four equivalent La(2), and one Ni(1) atom. In the second O site, O(2) is bonded to one La(2), three equivalent La(1), and one Ni(1) atom to form OLa4Ni trigonal bipyramids that share  a cornercorner with one O(4)La3Ni2 square pyramid, corners with six equivalent O(2)La4Ni trigonal bipyramids, and edges with three equivalent O(4)La3Ni2 square pyramids. In the third O site, O(3) is bonded in a 3-coordinate geometry to two equivalent La(2), three equivalent La(1), and one Ni(1) atom. In the fourth O site, O(4) is bonded to one La(1), two equivalent La(2), and two equivalent Ni(1) atoms to form distorted OLa3Ni2 square pyramids that share corners with four equivalent O(4)La3Ni2 square pyramids,  a cornercorner with one O(2)La4Ni trigonal bipyramid, and edges with three equivalent O(2)La4Ni trigonal bipyramids. is represented by the CIF file [CIF]
data_La2NiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.077
_cell_length_b   7.077
_cell_length_c   7.343
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   147.463
_symmetry_Int_Tables_number   1
_cell_volume   197.832
_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
  La  La0  1  0.284  0.716  0.144  1.0
  La  La1  1  0.716  0.284  0.644  1.0
  La  La2  1  0.053  0.947  0.348  1.0
  La  La3  1  0.947  0.053  0.848  1.0
  Ni  Ni4  1  0.610  0.390  0.037  1.0
  Ni  Ni5  1  0.390  0.610  0.537  1.0
  O  O6  1  0.543  0.457  0.636  1.0
  O  O7  1  0.766  0.234  0.983  1.0
  O  O8  1  0.353  0.647  0.793  1.0
  O  O9  1  0.234  0.766  0.483  1.0
  O  O10  1  0.647  0.353  0.293  1.0
  O  O11  1  0.898  0.102  0.496  1.0
  O  O12  1  0.457  0.543  0.136  1.0
  O  O13  1  0.102  0.898  0.996  1.0
[/CIF]
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