The material described by Ca(NiO2)2 is Spinel-like structured and crystallizes in the triclinic P1 space group. There are six inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(1), one O(17), one O(3), and one O(4) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(11)O6 octahedra,  a cornercorner with one Ni(7)O6 octahedra,  a cornercorner with one Ni(9)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, and corners with three equivalent Ca(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-74°. In the second Ca site, Ca(2) is bonded to one O(12), one O(2), one O(6), and one O(9) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra, corners with two equivalent Ni(6)O6 octahedra, corners with two equivalent Ni(8)O6 octahedra, and corners with three equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-66°. In the third Ca site, Ca(3) is bonded to one O(1), one O(21), one O(23), one O(24), one O(3), and one O(4) atom to form CaO6 octahedra that share corners with three equivalent Ca(1)O4 tetrahedra, corners with three equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(11)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(7)O6 octahedra, and  an edgeedge with one Ni(9)O6 octahedra. In the fourth Ca site, Ca(4) is bonded to one O(10), one O(14), one O(18), and one O(20) atom to form distorted CaO4 trigonal pyramids that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(6)O6 octahedra,  a cornercorner with one Ni(8)O6 octahedra, corners with two equivalent Ni(11)O6 octahedra, corners with two equivalent Ni(7)O6 octahedra, corners with two equivalent Ni(9)O6 octahedra, and corners with three equivalent Ni(10)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-73°. In the fifth Ca site, Ca(5) is bonded to one O(11), one O(16), one O(5), and one O(7) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(6)O6 octahedra,  a cornercorner with one Ni(8)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, and corners with three equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-68°. In the sixth Ca site, Ca(6) is bonded to one O(13), one O(15), one O(19), and one O(22) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(11)O6 octahedra,  a cornercorner with one Ni(7)O6 octahedra,  a cornercorner with one Ni(9)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra, corners with two equivalent Ni(6)O6 octahedra, corners with two equivalent Ni(8)O6 octahedra, and corners with three equivalent Ni(10)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-69°. There are twelve inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(11), one O(2), one O(3), one O(7), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ca(2)O4 tetrahedra,  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ca(1)O4 tetrahedra, corners with two equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ca(2)O4 tetrahedra,  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ca(1)O4 tetrahedra, corners with two equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(10), one O(15), one O(16), one O(19), one O(6), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ca(5)O4 tetrahedra, corners with two equivalent Ca(2)O4 tetrahedra, corners with two equivalent Ca(6)O4 tetrahedra,  a cornercorner with one Ca(4)O4 trigonal pyramid,  an edgeedge with one Ni(10)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(6)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(1), one O(11), one O(2), one O(4), one O(5), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ca(2)O4 tetrahedra,  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ca(1)O4 tetrahedra, corners with two equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. In the fifth Ni site, Ni(5) is bonded to one O(11), one O(12), one O(5), one O(6), one O(7), and one O(9) atom to form distorted NiO6 octahedra that share corners with three equivalent Ca(2)O4 tetrahedra, corners with three equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(6)O6 octahedra, and  an edgeedge with one Ni(8)O6 octahedra. In the sixth Ni site, Ni(6) is bonded to one O(10), one O(12), one O(13), one O(15), one O(16), and one O(9) atom to form distorted NiO6 octahedra that share  a cornercorner with one Ca(5)O4 tetrahedra, corners with two equivalent Ca(2)O4 tetrahedra, corners with two equivalent Ca(6)O4 tetrahedra,  a cornercorner with one Ca(4)O4 trigonal pyramid,  an edgeedge with one Ni(10)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the seventh Ni site, Ni(7) is bonded to one O(14), one O(17), one O(18), one O(22), one O(23), and one O(24) atom to form NiO6 octahedra that share  a cornercorner with one Ca(1)O4 tetrahedra,  a cornercorner with one Ca(6)O4 tetrahedra, corners with two equivalent Ni(12)O4 tetrahedra, corners with two equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(10)O6 octahedra, edges with two equivalent Ni(11)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the eighth Ni site, Ni(8) is bonded to one O(10), one O(12), one O(13), one O(16), one O(19), and one O(6) atom to form NiO6 octahedra that share  a cornercorner with one Ca(5)O4 tetrahedra, corners with two equivalent Ca(2)O4 tetrahedra, corners with two equivalent Ca(6)O4 tetrahedra,  a cornercorner with one Ca(4)O4 trigonal pyramid,  an edgeedge with one Ni(10)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. In the ninth Ni site, Ni(9) is bonded to one O(14), one O(17), one O(20), one O(21), one O(22), and one O(24) atom to form NiO6 octahedra that share  a cornercorner with one Ca(1)O4 tetrahedra,  a cornercorner with one Ca(6)O4 tetrahedra, corners with two equivalent Ni(12)O4 tetrahedra, corners with two equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(10)O6 octahedra, edges with two equivalent Ni(11)O6 octahedra, and edges with two equivalent Ni(7)O6 octahedra. In the tenth Ni site, Ni(10) is bonded to one O(13), one O(14), one O(15), one O(18), one O(19), and one O(20) atom to form NiO6 octahedra that share corners with three equivalent Ca(6)O4 tetrahedra, corners with three equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ni(11)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(6)O6 octahedra,  an edgeedge with one Ni(7)O6 octahedra,  an edgeedge with one Ni(8)O6 octahedra, and  an edgeedge with one Ni(9)O6 octahedra. In the eleventh Ni site, Ni(11) is bonded to one O(17), one O(18), one O(20), one O(21), one O(22), and one O(23) atom to form NiO6 octahedra that share  a cornercorner with one Ca(1)O4 tetrahedra,  a cornercorner with one Ca(6)O4 tetrahedra, corners with two equivalent Ni(12)O4 tetrahedra, corners with two equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(10)O6 octahedra, edges with two equivalent Ni(7)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the twelfth Ni site, Ni(12) is bonded to one O(21), one O(23), one O(24), and one O(8) atom to form NiO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(11)O6 octahedra, corners with two equivalent Ni(7)O6 octahedra, corners with two equivalent Ni(9)O6 octahedra, and corners with three equivalent Ca(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-63°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(3), one Ni(1), and one Ni(4) atom to form distorted OCa2Ni2 trigonal pyramids that share  a cornercorner with one O(17)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra, corners with two equivalent O(11)CaNi3 tetrahedra,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(3)Ca2Ni2 trigonal pyramid, and  an edgeedge with one O(4)Ca2Ni2 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Ca(2), one Ni(1), one Ni(2), and one Ni(4) atom. In the third O site, O(3) is bonded to one Ca(1), one Ca(3), one Ni(1), and one Ni(2) atom to form distorted OCa2Ni2 trigonal pyramids that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(17)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra, corners with two equivalent O(7)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(1)Ca2Ni2 trigonal pyramid, and  an edgeedge with one O(4)Ca2Ni2 trigonal pyramid. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(3), one Ni(2), and one Ni(4) atom to form distorted OCa2Ni2 trigonal pyramids that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(17)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra, corners with two equivalent O(5)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(1)Ca2Ni2 trigonal pyramid, and  an edgeedge with one O(3)Ca2Ni2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Ca(5), one Ni(2), one Ni(4), and one Ni(5) atom to form OCaNi3 tetrahedra that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(12)CaNi3 tetrahedra,  a cornercorner with one O(6)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra,  a cornercorner with one O(9)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(16)CaNi3 trigonal pyramid, corners with two equivalent O(4)Ca2Ni2 trigonal pyramids,  an edgeedge with one O(11)CaNi3 tetrahedra, and  an edgeedge with one O(7)CaNi3 tetrahedra. In the sixth O site, O(6) is bonded to one Ca(2), one Ni(3), one Ni(5), and one Ni(8) atom to form a mixture of corner and edge-sharing OCaNi3 tetrahedra. In the seventh O site, O(7) is bonded to one Ca(5), one Ni(1), one Ni(2), and one Ni(5) atom to form OCaNi3 tetrahedra that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(12)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra,  a cornercorner with one O(6)CaNi3 tetrahedra,  a cornercorner with one O(9)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(16)CaNi3 trigonal pyramid, corners with two equivalent O(3)Ca2Ni2 trigonal pyramids,  an edgeedge with one O(11)CaNi3 tetrahedra, and  an edgeedge with one O(5)CaNi3 tetrahedra. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Ni(1), one Ni(12), one Ni(2), and one Ni(4) atom. In the ninth O site, O(9) is bonded to one Ca(2), one Ni(3), one Ni(5), and one Ni(6) atom to form a mixture of corner and edge-sharing OCaNi3 tetrahedra. In the tenth O site, O(10) is bonded to one Ca(4), one Ni(3), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 trigonal pyramids. In the eleventh O site, O(11) is bonded to one Ca(5), one Ni(1), one Ni(4), and one Ni(5) atom to form OCaNi3 tetrahedra that share  a cornercorner with one O(12)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra,  a cornercorner with one O(6)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra,  a cornercorner with one O(9)CaNi3 tetrahedra,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(16)CaNi3 trigonal pyramid, corners with two equivalent O(1)Ca2Ni2 trigonal pyramids,  an edgeedge with one O(5)CaNi3 tetrahedra, and  an edgeedge with one O(7)CaNi3 tetrahedra. In the twelfth O site, O(12) is bonded to one Ca(2), one Ni(5), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the thirteenth O site, O(13) is bonded to one Ca(6), one Ni(10), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the fourteenth O site, O(14) is bonded to one Ca(4), one Ni(10), one Ni(7), and one Ni(9) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the fifteenth O site, O(15) is bonded to one Ca(6), one Ni(10), one Ni(3), and one Ni(6) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the sixteenth O site, O(16) is bonded to one Ca(5), one Ni(3), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 trigonal pyramids. In the seventeenth O site, O(17) is bonded to one Ca(1), one Ni(11), one Ni(7), and one Ni(9) atom to form OCaNi3 tetrahedra that share corners with three equivalent O(22)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(14)CaNi3 tetrahedra,  an edgeedge with one O(20)CaNi3 tetrahedra, and  an edgeedge with one O(18)CaNi3 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Ca(4), one Ni(10), one Ni(11), and one Ni(7) atom to form a mixture of distorted corner and edge-sharing OCaNi3 trigonal pyramids. In the nineteenth O site, O(19) is bonded to one Ca(6), one Ni(10), one Ni(3), and one Ni(8) atom to form a mixture of corner and edge-sharing OCaNi3 tetrahedra. In the twentieth O site, O(20) is bonded to one Ca(4), one Ni(10), one Ni(11), and one Ni(9) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the twenty-first O site, O(21) is bonded in a distorted rectangular see-saw-like geometry to one Ca(3), one Ni(11), one Ni(12), and one Ni(9) atom. In the twenty-second O site, O(22) is bonded to one Ca(6), one Ni(11), one Ni(7), and one Ni(9) atom to form corner-sharing OCaNi3 tetrahedra. In the twenty-third O site, O(23) is bonded in a distorted rectangular see-saw-like geometry to one Ca(3), one Ni(11), one Ni(12), and one Ni(7) atom. In the twenty-fourth O site, O(24) is bonded in a rectangular see-saw-like geometry to one Ca(3), one Ni(12), one Ni(7), and one Ni(9) atom. is represented by the CIF card [CIF]
data_Ca(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.093
_cell_length_b   6.196
_cell_length_c   14.854
_cell_angle_alpha   91.912
_cell_angle_beta   89.754
_cell_angle_gamma   119.266
_symmetry_Int_Tables_number   1
_cell_volume   488.939
_cell_formula_units_Z   6
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  0.832  0.667  0.958  1.0
  Ca  Ca1  1  0.502  0.000  0.613  1.0
  Ca  Ca2  1  0.501  0.003  0.004  1.0
  Ca  Ca3  1  0.165  0.331  0.274  1.0
  Ca  Ca4  1  0.831  0.663  0.717  1.0
  Ca  Ca5  1  0.501  0.003  0.369  1.0
  Ni  Ni6  1  0.331  0.162  0.830  1.0
  Ni  Ni7  1  0.334  0.669  0.828  1.0
  Ni  Ni8  1  0.004  0.501  0.497  1.0
  Ni  Ni9  1  0.831  0.162  0.829  1.0
  Ni  Ni10  1  0.166  0.327  0.664  1.0
  Ni  Ni11  1  0.003  0.004  0.498  1.0
  Ni  Ni12  1  0.670  0.825  0.171  1.0
  Ni  Ni13  1  0.499  0.500  0.497  1.0
  Ni  Ni14  1  0.155  0.824  0.172  1.0
  Ni  Ni15  1  0.836  0.676  0.339  1.0
  Ni  Ni16  1  0.672  0.346  0.172  1.0
  Ni  Ni17  1  0.167  0.334  0.047  1.0
  O  O18  1  0.646  0.295  0.892  1.0
  O  O19  1  0.495  0.994  0.756  1.0
  O  O20  1  0.199  0.850  0.892  1.0
  O  O21  1  0.651  0.849  0.890  1.0
  O  O22  1  0.025  0.462  0.760  1.0
  O  O23  1  0.314  0.610  0.573  1.0
  O  O24  1  0.433  0.459  0.758  1.0
  O  O25  1  0.168  0.334  0.922  1.0
  O  O26  1  0.895  0.188  0.574  1.0
  O  O27  1  0.177  0.362  0.429  1.0
  O  O28  1  0.028  0.054  0.762  1.0
  O  O29  1  0.295  0.179  0.570  1.0
  O  O30  1  0.708  0.827  0.424  1.0
  O  O31  1  0.967  0.934  0.261  1.0
  O  O32  1  0.114  0.819  0.423  1.0
  O  O33  1  0.824  0.636  0.566  1.0
  O  O34  1  0.829  0.656  0.108  1.0
  O  O35  1  0.564  0.542  0.261  1.0
  O  O36  1  0.694  0.399  0.418  1.0
  O  O37  1  0.970  0.536  0.261  1.0
  O  O38  1  0.324  0.174  0.101  1.0
  O  O39  1  0.503  0.009  0.222  1.0
  O  O40  1  0.848  0.172  0.100  1.0
  O  O41  1  0.330  0.661  0.097  1.0
[/CIF]
.
The material described by Ca(NiO2)2 is Spinel-like structured and crystallizes in the triclinic P1 space group. There are six inequivalent Ca sites. In the first Ca site, Ca(1) is bonded to one O(1), one O(17), one O(3), and one O(4) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(11)O6 octahedra,  a cornercorner with one Ni(7)O6 octahedra,  a cornercorner with one Ni(9)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, and corners with three equivalent Ca(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 55-74°. In the second Ca site, Ca(2) is bonded to one O(12), one O(2), one O(6), and one O(9) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra, corners with two equivalent Ni(6)O6 octahedra, corners with two equivalent Ni(8)O6 octahedra, and corners with three equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-66°. In the third Ca site, Ca(3) is bonded to one O(1), one O(21), one O(23), one O(24), one O(3), and one O(4) atom to form CaO6 octahedra that share corners with three equivalent Ca(1)O4 tetrahedra, corners with three equivalent Ni(12)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(11)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(7)O6 octahedra, and  an edgeedge with one Ni(9)O6 octahedra. In the fourth Ca site, Ca(4) is bonded to one O(10), one O(14), one O(18), and one O(20) atom to form distorted CaO4 trigonal pyramids that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(6)O6 octahedra,  a cornercorner with one Ni(8)O6 octahedra, corners with two equivalent Ni(11)O6 octahedra, corners with two equivalent Ni(7)O6 octahedra, corners with two equivalent Ni(9)O6 octahedra, and corners with three equivalent Ni(10)O6 octahedra. The corner-sharing octahedral tilt angles range from 44-73°. In the fifth Ca site, Ca(5) is bonded to one O(11), one O(16), one O(5), and one O(7) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(3)O6 octahedra,  a cornercorner with one Ni(6)O6 octahedra,  a cornercorner with one Ni(8)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, corners with two equivalent Ni(2)O6 octahedra, corners with two equivalent Ni(4)O6 octahedra, and corners with three equivalent Ni(5)O6 octahedra. The corner-sharing octahedral tilt angles range from 57-68°. In the sixth Ca site, Ca(6) is bonded to one O(13), one O(15), one O(19), and one O(22) atom to form CaO4 tetrahedra that share  a cornercorner with one Ni(11)O6 octahedra,  a cornercorner with one Ni(7)O6 octahedra,  a cornercorner with one Ni(9)O6 octahedra, corners with two equivalent Ni(3)O6 octahedra, corners with two equivalent Ni(6)O6 octahedra, corners with two equivalent Ni(8)O6 octahedra, and corners with three equivalent Ni(10)O6 octahedra. The corner-sharing octahedral tilt angles range from 56-69°. There are twelve inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(1), one O(11), one O(2), one O(3), one O(7), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ca(2)O4 tetrahedra,  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ca(1)O4 tetrahedra, corners with two equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(2)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the second Ni site, Ni(2) is bonded to one O(2), one O(3), one O(4), one O(5), one O(7), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ca(2)O4 tetrahedra,  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ca(1)O4 tetrahedra, corners with two equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(4)O6 octahedra. In the third Ni site, Ni(3) is bonded to one O(10), one O(15), one O(16), one O(19), one O(6), and one O(9) atom to form NiO6 octahedra that share  a cornercorner with one Ca(5)O4 tetrahedra, corners with two equivalent Ca(2)O4 tetrahedra, corners with two equivalent Ca(6)O4 tetrahedra,  a cornercorner with one Ca(4)O4 trigonal pyramid,  an edgeedge with one Ni(10)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(6)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the fourth Ni site, Ni(4) is bonded to one O(1), one O(11), one O(2), one O(4), one O(5), and one O(8) atom to form NiO6 octahedra that share  a cornercorner with one Ca(2)O4 tetrahedra,  a cornercorner with one Ni(12)O4 tetrahedra, corners with two equivalent Ca(1)O4 tetrahedra, corners with two equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with two equivalent Ni(2)O6 octahedra. In the fifth Ni site, Ni(5) is bonded to one O(11), one O(12), one O(5), one O(6), one O(7), and one O(9) atom to form distorted NiO6 octahedra that share corners with three equivalent Ca(2)O4 tetrahedra, corners with three equivalent Ca(5)O4 tetrahedra,  an edgeedge with one Ni(1)O6 octahedra,  an edgeedge with one Ni(2)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(4)O6 octahedra,  an edgeedge with one Ni(6)O6 octahedra, and  an edgeedge with one Ni(8)O6 octahedra. In the sixth Ni site, Ni(6) is bonded to one O(10), one O(12), one O(13), one O(15), one O(16), and one O(9) atom to form distorted NiO6 octahedra that share  a cornercorner with one Ca(5)O4 tetrahedra, corners with two equivalent Ca(2)O4 tetrahedra, corners with two equivalent Ca(6)O4 tetrahedra,  a cornercorner with one Ca(4)O4 trigonal pyramid,  an edgeedge with one Ni(10)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(8)O6 octahedra. In the seventh Ni site, Ni(7) is bonded to one O(14), one O(17), one O(18), one O(22), one O(23), and one O(24) atom to form NiO6 octahedra that share  a cornercorner with one Ca(1)O4 tetrahedra,  a cornercorner with one Ca(6)O4 tetrahedra, corners with two equivalent Ni(12)O4 tetrahedra, corners with two equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(10)O6 octahedra, edges with two equivalent Ni(11)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the eighth Ni site, Ni(8) is bonded to one O(10), one O(12), one O(13), one O(16), one O(19), and one O(6) atom to form NiO6 octahedra that share  a cornercorner with one Ca(5)O4 tetrahedra, corners with two equivalent Ca(2)O4 tetrahedra, corners with two equivalent Ca(6)O4 tetrahedra,  a cornercorner with one Ca(4)O4 trigonal pyramid,  an edgeedge with one Ni(10)O6 octahedra,  an edgeedge with one Ni(5)O6 octahedra, edges with two equivalent Ni(3)O6 octahedra, and edges with two equivalent Ni(6)O6 octahedra. In the ninth Ni site, Ni(9) is bonded to one O(14), one O(17), one O(20), one O(21), one O(22), and one O(24) atom to form NiO6 octahedra that share  a cornercorner with one Ca(1)O4 tetrahedra,  a cornercorner with one Ca(6)O4 tetrahedra, corners with two equivalent Ni(12)O4 tetrahedra, corners with two equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(10)O6 octahedra, edges with two equivalent Ni(11)O6 octahedra, and edges with two equivalent Ni(7)O6 octahedra. In the tenth Ni site, Ni(10) is bonded to one O(13), one O(14), one O(15), one O(18), one O(19), and one O(20) atom to form NiO6 octahedra that share corners with three equivalent Ca(6)O4 tetrahedra, corners with three equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ni(11)O6 octahedra,  an edgeedge with one Ni(3)O6 octahedra,  an edgeedge with one Ni(6)O6 octahedra,  an edgeedge with one Ni(7)O6 octahedra,  an edgeedge with one Ni(8)O6 octahedra, and  an edgeedge with one Ni(9)O6 octahedra. In the eleventh Ni site, Ni(11) is bonded to one O(17), one O(18), one O(20), one O(21), one O(22), and one O(23) atom to form NiO6 octahedra that share  a cornercorner with one Ca(1)O4 tetrahedra,  a cornercorner with one Ca(6)O4 tetrahedra, corners with two equivalent Ni(12)O4 tetrahedra, corners with two equivalent Ca(4)O4 trigonal pyramids,  an edgeedge with one Ca(3)O6 octahedra,  an edgeedge with one Ni(10)O6 octahedra, edges with two equivalent Ni(7)O6 octahedra, and edges with two equivalent Ni(9)O6 octahedra. In the twelfth Ni site, Ni(12) is bonded to one O(21), one O(23), one O(24), and one O(8) atom to form NiO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra,  a cornercorner with one Ni(2)O6 octahedra,  a cornercorner with one Ni(4)O6 octahedra, corners with two equivalent Ni(11)O6 octahedra, corners with two equivalent Ni(7)O6 octahedra, corners with two equivalent Ni(9)O6 octahedra, and corners with three equivalent Ca(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-63°. There are twenty-four inequivalent O sites. In the first O site, O(1) is bonded to one Ca(1), one Ca(3), one Ni(1), and one Ni(4) atom to form distorted OCa2Ni2 trigonal pyramids that share  a cornercorner with one O(17)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra, corners with two equivalent O(11)CaNi3 tetrahedra,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(3)Ca2Ni2 trigonal pyramid, and  an edgeedge with one O(4)Ca2Ni2 trigonal pyramid. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Ca(2), one Ni(1), one Ni(2), and one Ni(4) atom. In the third O site, O(3) is bonded to one Ca(1), one Ca(3), one Ni(1), and one Ni(2) atom to form distorted OCa2Ni2 trigonal pyramids that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(17)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra, corners with two equivalent O(7)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(1)Ca2Ni2 trigonal pyramid, and  an edgeedge with one O(4)Ca2Ni2 trigonal pyramid. In the fourth O site, O(4) is bonded to one Ca(1), one Ca(3), one Ni(2), and one Ni(4) atom to form distorted OCa2Ni2 trigonal pyramids that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(17)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra, corners with two equivalent O(5)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(1)Ca2Ni2 trigonal pyramid, and  an edgeedge with one O(3)Ca2Ni2 trigonal pyramid. In the fifth O site, O(5) is bonded to one Ca(5), one Ni(2), one Ni(4), and one Ni(5) atom to form OCaNi3 tetrahedra that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(12)CaNi3 tetrahedra,  a cornercorner with one O(6)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra,  a cornercorner with one O(9)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(16)CaNi3 trigonal pyramid, corners with two equivalent O(4)Ca2Ni2 trigonal pyramids,  an edgeedge with one O(11)CaNi3 tetrahedra, and  an edgeedge with one O(7)CaNi3 tetrahedra. In the sixth O site, O(6) is bonded to one Ca(2), one Ni(3), one Ni(5), and one Ni(8) atom to form a mixture of corner and edge-sharing OCaNi3 tetrahedra. In the seventh O site, O(7) is bonded to one Ca(5), one Ni(1), one Ni(2), and one Ni(5) atom to form OCaNi3 tetrahedra that share  a cornercorner with one O(11)CaNi3 tetrahedra,  a cornercorner with one O(12)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra,  a cornercorner with one O(6)CaNi3 tetrahedra,  a cornercorner with one O(9)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(16)CaNi3 trigonal pyramid, corners with two equivalent O(3)Ca2Ni2 trigonal pyramids,  an edgeedge with one O(11)CaNi3 tetrahedra, and  an edgeedge with one O(5)CaNi3 tetrahedra. In the eighth O site, O(8) is bonded in a rectangular see-saw-like geometry to one Ni(1), one Ni(12), one Ni(2), and one Ni(4) atom. In the ninth O site, O(9) is bonded to one Ca(2), one Ni(3), one Ni(5), and one Ni(6) atom to form a mixture of corner and edge-sharing OCaNi3 tetrahedra. In the tenth O site, O(10) is bonded to one Ca(4), one Ni(3), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 trigonal pyramids. In the eleventh O site, O(11) is bonded to one Ca(5), one Ni(1), one Ni(4), and one Ni(5) atom to form OCaNi3 tetrahedra that share  a cornercorner with one O(12)CaNi3 tetrahedra,  a cornercorner with one O(5)CaNi3 tetrahedra,  a cornercorner with one O(6)CaNi3 tetrahedra,  a cornercorner with one O(7)CaNi3 tetrahedra,  a cornercorner with one O(9)CaNi3 tetrahedra,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(16)CaNi3 trigonal pyramid, corners with two equivalent O(1)Ca2Ni2 trigonal pyramids,  an edgeedge with one O(5)CaNi3 tetrahedra, and  an edgeedge with one O(7)CaNi3 tetrahedra. In the twelfth O site, O(12) is bonded to one Ca(2), one Ni(5), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the thirteenth O site, O(13) is bonded to one Ca(6), one Ni(10), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the fourteenth O site, O(14) is bonded to one Ca(4), one Ni(10), one Ni(7), and one Ni(9) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the fifteenth O site, O(15) is bonded to one Ca(6), one Ni(10), one Ni(3), and one Ni(6) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the sixteenth O site, O(16) is bonded to one Ca(5), one Ni(3), one Ni(6), and one Ni(8) atom to form a mixture of distorted corner and edge-sharing OCaNi3 trigonal pyramids. In the seventeenth O site, O(17) is bonded to one Ca(1), one Ni(11), one Ni(7), and one Ni(9) atom to form OCaNi3 tetrahedra that share corners with three equivalent O(22)CaNi3 tetrahedra,  a cornercorner with one O(1)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(3)Ca2Ni2 trigonal pyramid,  a cornercorner with one O(4)Ca2Ni2 trigonal pyramid,  an edgeedge with one O(14)CaNi3 tetrahedra,  an edgeedge with one O(20)CaNi3 tetrahedra, and  an edgeedge with one O(18)CaNi3 trigonal pyramid. In the eighteenth O site, O(18) is bonded to one Ca(4), one Ni(10), one Ni(11), and one Ni(7) atom to form a mixture of distorted corner and edge-sharing OCaNi3 trigonal pyramids. In the nineteenth O site, O(19) is bonded to one Ca(6), one Ni(10), one Ni(3), and one Ni(8) atom to form a mixture of corner and edge-sharing OCaNi3 tetrahedra. In the twentieth O site, O(20) is bonded to one Ca(4), one Ni(10), one Ni(11), and one Ni(9) atom to form a mixture of distorted corner and edge-sharing OCaNi3 tetrahedra. In the twenty-first O site, O(21) is bonded in a distorted rectangular see-saw-like geometry to one Ca(3), one Ni(11), one Ni(12), and one Ni(9) atom. In the twenty-second O site, O(22) is bonded to one Ca(6), one Ni(11), one Ni(7), and one Ni(9) atom to form corner-sharing OCaNi3 tetrahedra. In the twenty-third O site, O(23) is bonded in a distorted rectangular see-saw-like geometry to one Ca(3), one Ni(11), one Ni(12), and one Ni(7) atom. In the twenty-fourth O site, O(24) is bonded in a rectangular see-saw-like geometry to one Ca(3), one Ni(12), one Ni(7), and one Ni(9) atom. is represented by the CIF card [CIF]
data_Ca(NiO2)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.093
_cell_length_b   6.196
_cell_length_c   14.854
_cell_angle_alpha   91.912
_cell_angle_beta   89.754
_cell_angle_gamma   119.266
_symmetry_Int_Tables_number   1
_cell_volume   488.939
_cell_formula_units_Z   6
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  0.832  0.667  0.958  1.0
  Ca  Ca1  1  0.502  0.000  0.613  1.0
  Ca  Ca2  1  0.501  0.003  0.004  1.0
  Ca  Ca3  1  0.165  0.331  0.274  1.0
  Ca  Ca4  1  0.831  0.663  0.717  1.0
  Ca  Ca5  1  0.501  0.003  0.369  1.0
  Ni  Ni6  1  0.331  0.162  0.830  1.0
  Ni  Ni7  1  0.334  0.669  0.828  1.0
  Ni  Ni8  1  0.004  0.501  0.497  1.0
  Ni  Ni9  1  0.831  0.162  0.829  1.0
  Ni  Ni10  1  0.166  0.327  0.664  1.0
  Ni  Ni11  1  0.003  0.004  0.498  1.0
  Ni  Ni12  1  0.670  0.825  0.171  1.0
  Ni  Ni13  1  0.499  0.500  0.497  1.0
  Ni  Ni14  1  0.155  0.824  0.172  1.0
  Ni  Ni15  1  0.836  0.676  0.339  1.0
  Ni  Ni16  1  0.672  0.346  0.172  1.0
  Ni  Ni17  1  0.167  0.334  0.047  1.0
  O  O18  1  0.646  0.295  0.892  1.0
  O  O19  1  0.495  0.994  0.756  1.0
  O  O20  1  0.199  0.850  0.892  1.0
  O  O21  1  0.651  0.849  0.890  1.0
  O  O22  1  0.025  0.462  0.760  1.0
  O  O23  1  0.314  0.610  0.573  1.0
  O  O24  1  0.433  0.459  0.758  1.0
  O  O25  1  0.168  0.334  0.922  1.0
  O  O26  1  0.895  0.188  0.574  1.0
  O  O27  1  0.177  0.362  0.429  1.0
  O  O28  1  0.028  0.054  0.762  1.0
  O  O29  1  0.295  0.179  0.570  1.0
  O  O30  1  0.708  0.827  0.424  1.0
  O  O31  1  0.967  0.934  0.261  1.0
  O  O32  1  0.114  0.819  0.423  1.0
  O  O33  1  0.824  0.636  0.566  1.0
  O  O34  1  0.829  0.656  0.108  1.0
  O  O35  1  0.564  0.542  0.261  1.0
  O  O36  1  0.694  0.399  0.418  1.0
  O  O37  1  0.970  0.536  0.261  1.0
  O  O38  1  0.324  0.174  0.101  1.0
  O  O39  1  0.503  0.009  0.222  1.0
  O  O40  1  0.848  0.172  0.100  1.0
  O  O41  1  0.330  0.661  0.097  1.0
[/CIF]
.