The material described by Ca2Nb2O7 crystallizes in the cubic Fd-3m space group. Ca(1) is bonded to two equivalent O(1) and six equivalent O(2) atoms to form distorted CaO8 hexagonal bipyramids that share edges with six equivalent Ca(1)O8 hexagonal bipyramids and edges with six equivalent Nb(1)O6 octahedra. Nb(1) is bonded to six equivalent O(2) atoms to form NbO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra and edges with six equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 42°. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) atoms to form corner-sharing OCa4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Nb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.484
_cell_length_b   7.484
_cell_length_c   7.484
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   296.359
_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  0.125  0.625  0.125  1.0
  Ca  Ca1  1  0.125  0.125  0.625  1.0
  Ca  Ca2  1  0.625  0.125  0.125  1.0
  Ca  Ca3  1  0.125  0.125  0.125  1.0
  Nb  Nb4  1  0.625  0.125  0.625  1.0
  Nb  Nb5  1  0.625  0.625  0.125  1.0
  Nb  Nb6  1  0.125  0.625  0.625  1.0
  Nb  Nb7  1  0.625  0.625  0.625  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.250  0.250  0.250  1.0
  O  O10  1  0.307  0.307  0.693  1.0
  O  O11  1  0.557  0.557  0.943  1.0
  O  O12  1  0.693  0.307  0.693  1.0
  O  O13  1  0.693  0.307  0.307  1.0
  O  O14  1  0.307  0.693  0.693  1.0
  O  O15  1  0.307  0.693  0.307  1.0
  O  O16  1  0.693  0.693  0.307  1.0
  O  O17  1  0.943  0.557  0.557  1.0
  O  O18  1  0.557  0.943  0.943  1.0
  O  O19  1  0.943  0.943  0.557  1.0
  O  O20  1  0.943  0.557  0.943  1.0
  O  O21  1  0.557  0.943  0.557  1.0
[/CIF]
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The material described by Ca2Nb2O7 crystallizes in the cubic Fd-3m space group. Ca(1) is bonded to two equivalent O(1) and six equivalent O(2) atoms to form distorted CaO8 hexagonal bipyramids that share edges with six equivalent Ca(1)O8 hexagonal bipyramids and edges with six equivalent Nb(1)O6 octahedra. Nb(1) is bonded to six equivalent O(2) atoms to form NbO6 octahedra that share corners with six equivalent Nb(1)O6 octahedra and edges with six equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 42°. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent Ca(1) atoms to form corner-sharing OCa4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Nb(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Nb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.484
_cell_length_b   7.484
_cell_length_c   7.484
_cell_angle_alpha   60.000
_cell_angle_beta   60.000
_cell_angle_gamma   60.000
_symmetry_Int_Tables_number   1
_cell_volume   296.359
_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  0.125  0.625  0.125  1.0
  Ca  Ca1  1  0.125  0.125  0.625  1.0
  Ca  Ca2  1  0.625  0.125  0.125  1.0
  Ca  Ca3  1  0.125  0.125  0.125  1.0
  Nb  Nb4  1  0.625  0.125  0.625  1.0
  Nb  Nb5  1  0.625  0.625  0.125  1.0
  Nb  Nb6  1  0.125  0.625  0.625  1.0
  Nb  Nb7  1  0.625  0.625  0.625  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.250  0.250  0.250  1.0
  O  O10  1  0.307  0.307  0.693  1.0
  O  O11  1  0.557  0.557  0.943  1.0
  O  O12  1  0.693  0.307  0.693  1.0
  O  O13  1  0.693  0.307  0.307  1.0
  O  O14  1  0.307  0.693  0.693  1.0
  O  O15  1  0.307  0.693  0.307  1.0
  O  O16  1  0.693  0.693  0.307  1.0
  O  O17  1  0.943  0.557  0.557  1.0
  O  O18  1  0.557  0.943  0.943  1.0
  O  O19  1  0.943  0.943  0.557  1.0
  O  O20  1  0.943  0.557  0.943  1.0
  O  O21  1  0.557  0.943  0.557  1.0
[/CIF]
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