The crystal structure described by Ca2Nb2CuO8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 5-coordinate geometry to two equivalent O(3) and three equivalent O(4) atoms. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted edge-sharing NbO6 octahedra. Cu(1) is bonded in a see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Nb(1) and one Cu(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Nb(1) and one Cu(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Ca(1) and one Nb(1) atom to form a mixture of distorted corner and edge-sharing OCa3Nb trigonal pyramids. is represented by the CIF card [CIF]
data_Ca2Nb2CuO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.133
_cell_length_b   10.133
_cell_length_c   5.469
_cell_angle_alpha   86.983
_cell_angle_beta   86.983
_cell_angle_gamma   38.823
_symmetry_Int_Tables_number   1
_cell_volume   351.476
_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
  Ca  Ca0  1  0.466  0.121  0.744  1.0
  Ca  Ca1  1  0.879  0.534  0.756  1.0
  Ca  Ca2  1  0.534  0.879  0.256  1.0
  Ca  Ca3  1  0.121  0.466  0.244  1.0
  Nb  Nb4  1  0.261  0.974  0.765  1.0
  Nb  Nb5  1  0.026  0.739  0.735  1.0
  Nb  Nb6  1  0.739  0.026  0.235  1.0
  Nb  Nb7  1  0.974  0.261  0.265  1.0
  Cu  Cu8  1  0.736  0.264  0.750  1.0
  Cu  Cu9  1  0.264  0.736  0.250  1.0
  O  O10  1  0.198  0.954  0.434  1.0
  O  O11  1  0.046  0.802  0.066  1.0
  O  O12  1  0.802  0.046  0.566  1.0
  O  O13  1  0.954  0.198  0.934  1.0
  O  O14  1  0.360  0.759  0.969  1.0
  O  O15  1  0.241  0.640  0.531  1.0
  O  O16  1  0.640  0.241  0.031  1.0
  O  O17  1  0.759  0.360  0.469  1.0
  O  O18  1  0.248  0.128  0.012  1.0
  O  O19  1  0.872  0.752  0.488  1.0
  O  O20  1  0.838  0.533  0.171  1.0
  O  O21  1  0.467  0.162  0.329  1.0
  O  O22  1  0.162  0.467  0.829  1.0
  O  O23  1  0.533  0.838  0.671  1.0
  O  O24  1  0.128  0.248  0.512  1.0
  O  O25  1  0.752  0.872  0.988  1.0
[/CIF]
.
The crystal structure described by Ca2Nb2CuO8 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 5-coordinate geometry to two equivalent O(3) and three equivalent O(4) atoms. Nb(1) is bonded to one O(2), one O(4), two equivalent O(1), and two equivalent O(3) atoms to form distorted edge-sharing NbO6 octahedra. Cu(1) is bonded in a see-saw-like geometry to two equivalent O(1) and two equivalent O(2) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Nb(1) and one Cu(1) atom. In the second O site, O(2) is bonded in a bent 150 degrees geometry to one Nb(1) and one Cu(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. In the fourth O site, O(4) is bonded to three equivalent Ca(1) and one Nb(1) atom to form a mixture of distorted corner and edge-sharing OCa3Nb trigonal pyramids. is represented by the CIF card [CIF]
data_Ca2Nb2CuO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.133
_cell_length_b   10.133
_cell_length_c   5.469
_cell_angle_alpha   86.983
_cell_angle_beta   86.983
_cell_angle_gamma   38.823
_symmetry_Int_Tables_number   1
_cell_volume   351.476
_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
  Ca  Ca0  1  0.466  0.121  0.744  1.0
  Ca  Ca1  1  0.879  0.534  0.756  1.0
  Ca  Ca2  1  0.534  0.879  0.256  1.0
  Ca  Ca3  1  0.121  0.466  0.244  1.0
  Nb  Nb4  1  0.261  0.974  0.765  1.0
  Nb  Nb5  1  0.026  0.739  0.735  1.0
  Nb  Nb6  1  0.739  0.026  0.235  1.0
  Nb  Nb7  1  0.974  0.261  0.265  1.0
  Cu  Cu8  1  0.736  0.264  0.750  1.0
  Cu  Cu9  1  0.264  0.736  0.250  1.0
  O  O10  1  0.198  0.954  0.434  1.0
  O  O11  1  0.046  0.802  0.066  1.0
  O  O12  1  0.802  0.046  0.566  1.0
  O  O13  1  0.954  0.198  0.934  1.0
  O  O14  1  0.360  0.759  0.969  1.0
  O  O15  1  0.241  0.640  0.531  1.0
  O  O16  1  0.640  0.241  0.031  1.0
  O  O17  1  0.759  0.360  0.469  1.0
  O  O18  1  0.248  0.128  0.012  1.0
  O  O19  1  0.872  0.752  0.488  1.0
  O  O20  1  0.838  0.533  0.171  1.0
  O  O21  1  0.467  0.162  0.329  1.0
  O  O22  1  0.162  0.467  0.829  1.0
  O  O23  1  0.533  0.838  0.671  1.0
  O  O24  1  0.128  0.248  0.512  1.0
  O  O25  1  0.752  0.872  0.988  1.0
[/CIF]
.