The structure described by NiOCaO crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted CaO5 trigonal bipyramids that share corners with two equivalent Ni(2)O6 octahedra, edges with three equivalent Ni(2)O6 octahedra, and edges with two equivalent Ca(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the second Ca site, Ca(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Ni site, Ni(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ca(1)O5 trigonal bipyramids, edges with four equivalent Ni(2)O6 octahedra, and edges with three equivalent Ca(1)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(2), one Ni(2), and two equivalent Ni(1) atoms to form OCa2Ni3 trigonal bipyramids that share  a cornercorner with one O(4)Ca2Ni4 octahedra, corners with two equivalent O(1)Ca2Ni3 trigonal bipyramids, corners with two equivalent O(2)Ca3Ni2 trigonal bipyramids, edges with two equivalent O(4)Ca2Ni4 octahedra,  an edgeedge with one O(1)Ca2Ni3 trigonal bipyramid, and edges with two equivalent O(2)Ca3Ni2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 2°. In the second O site, O(2) is bonded to one Ca(1), two equivalent Ca(2), and two equivalent Ni(2) atoms to form distorted OCa3Ni2 trigonal bipyramids that share corners with two equivalent O(4)Ca2Ni4 octahedra, corners with two equivalent O(1)Ca2Ni3 trigonal bipyramids, edges with three equivalent O(4)Ca2Ni4 octahedra, edges with two equivalent O(1)Ca2Ni3 trigonal bipyramids, and edges with two equivalent O(2)Ca3Ni2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-6°. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(2), two equivalent Ca(1), and two equivalent Ni(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Ca(1), one Ni(1), and three equivalent Ni(2) atoms to form OCa2Ni4 octahedra that share  a cornercorner with one O(1)Ca2Ni3 trigonal bipyramid, corners with two equivalent O(2)Ca3Ni2 trigonal bipyramids, edges with four equivalent O(4)Ca2Ni4 octahedra, edges with two equivalent O(1)Ca2Ni3 trigonal bipyramids, and edges with three equivalent O(2)Ca3Ni2 trigonal bipyramids. is represented by the CIF card [CIF]
data_CaNiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.168
_cell_length_b   8.172
_cell_length_c   8.936
_cell_angle_alpha   111.027
_cell_angle_beta   99.972
_cell_angle_gamma   89.160
_symmetry_Int_Tables_number   1
_cell_volume   212.425
_cell_formula_units_Z   4
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  0.687  0.145  0.366  1.0
  Ca  Ca1  1  0.313  0.855  0.634  1.0
  Ca  Ca2  1  0.994  0.703  0.979  1.0
  Ca  Ca3  1  0.006  0.297  0.021  1.0
  Ni  Ni4  1  0.378  0.253  0.717  1.0
  Ni  Ni5  1  0.826  0.525  0.649  1.0
  Ni  Ni6  1  0.174  0.475  0.351  1.0
  Ni  Ni7  1  0.622  0.747  0.283  1.0
  O  O8  1  0.093  0.585  0.178  1.0
  O  O9  1  0.603  0.289  0.196  1.0
  O  O10  1  0.397  0.711  0.804  1.0
  O  O11  1  0.907  0.415  0.822  1.0
  O  O12  1  0.840  0.075  0.716  1.0
  O  O13  1  0.264  0.354  0.525  1.0
  O  O14  1  0.160  0.925  0.284  1.0
  O  O15  1  0.736  0.646  0.475  1.0
[/CIF]
.
The structure described by NiOCaO crystallizes in the triclinic P-1 space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(2), two equivalent O(3), and two equivalent O(4) atoms to form distorted CaO5 trigonal bipyramids that share corners with two equivalent Ni(2)O6 octahedra, edges with three equivalent Ni(2)O6 octahedra, and edges with two equivalent Ca(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 6°. In the second Ca site, Ca(2) is bonded in a 5-coordinate geometry to one O(3), two equivalent O(1), and two equivalent O(2) atoms. There are two inequivalent Ni sites. In the first Ni site, Ni(1) is bonded in a 5-coordinate geometry to one O(4), two equivalent O(1), and two equivalent O(3) atoms. In the second Ni site, Ni(2) is bonded to one O(1), two equivalent O(2), and three equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent Ca(1)O5 trigonal bipyramids, edges with four equivalent Ni(2)O6 octahedra, and edges with three equivalent Ca(1)O5 trigonal bipyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ca(2), one Ni(2), and two equivalent Ni(1) atoms to form OCa2Ni3 trigonal bipyramids that share  a cornercorner with one O(4)Ca2Ni4 octahedra, corners with two equivalent O(1)Ca2Ni3 trigonal bipyramids, corners with two equivalent O(2)Ca3Ni2 trigonal bipyramids, edges with two equivalent O(4)Ca2Ni4 octahedra,  an edgeedge with one O(1)Ca2Ni3 trigonal bipyramid, and edges with two equivalent O(2)Ca3Ni2 trigonal bipyramids. The corner-sharing octahedral tilt angles are 2°. In the second O site, O(2) is bonded to one Ca(1), two equivalent Ca(2), and two equivalent Ni(2) atoms to form distorted OCa3Ni2 trigonal bipyramids that share corners with two equivalent O(4)Ca2Ni4 octahedra, corners with two equivalent O(1)Ca2Ni3 trigonal bipyramids, edges with three equivalent O(4)Ca2Ni4 octahedra, edges with two equivalent O(1)Ca2Ni3 trigonal bipyramids, and edges with two equivalent O(2)Ca3Ni2 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 5-6°. In the third O site, O(3) is bonded in a 5-coordinate geometry to one Ca(2), two equivalent Ca(1), and two equivalent Ni(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Ca(1), one Ni(1), and three equivalent Ni(2) atoms to form OCa2Ni4 octahedra that share  a cornercorner with one O(1)Ca2Ni3 trigonal bipyramid, corners with two equivalent O(2)Ca3Ni2 trigonal bipyramids, edges with four equivalent O(4)Ca2Ni4 octahedra, edges with two equivalent O(1)Ca2Ni3 trigonal bipyramids, and edges with three equivalent O(2)Ca3Ni2 trigonal bipyramids. is represented by the CIF card [CIF]
data_CaNiO2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.168
_cell_length_b   8.172
_cell_length_c   8.936
_cell_angle_alpha   111.027
_cell_angle_beta   99.972
_cell_angle_gamma   89.160
_symmetry_Int_Tables_number   1
_cell_volume   212.425
_cell_formula_units_Z   4
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  0.687  0.145  0.366  1.0
  Ca  Ca1  1  0.313  0.855  0.634  1.0
  Ca  Ca2  1  0.994  0.703  0.979  1.0
  Ca  Ca3  1  0.006  0.297  0.021  1.0
  Ni  Ni4  1  0.378  0.253  0.717  1.0
  Ni  Ni5  1  0.826  0.525  0.649  1.0
  Ni  Ni6  1  0.174  0.475  0.351  1.0
  Ni  Ni7  1  0.622  0.747  0.283  1.0
  O  O8  1  0.093  0.585  0.178  1.0
  O  O9  1  0.603  0.289  0.196  1.0
  O  O10  1  0.397  0.711  0.804  1.0
  O  O11  1  0.907  0.415  0.822  1.0
  O  O12  1  0.840  0.075  0.716  1.0
  O  O13  1  0.264  0.354  0.525  1.0
  O  O14  1  0.160  0.925  0.284  1.0
  O  O15  1  0.736  0.646  0.475  1.0
[/CIF]
.