The crystal structure described by Ca2Sb2O7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms to form distorted CaO8 hexagonal bipyramids that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with two equivalent Sb(2)O6 octahedra, edges with two equivalent Sb(2)O6 octahedra, and edges with four equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra, and edges with four equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-46°. In the second Sb site, Sb(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with four equivalent Sb(1)O6 octahedra, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 46°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Sb(1), and one Sb(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(2) and two equivalent Sb(1) atoms. In the third O site, O(3) is bonded to one Ca(2), two equivalent Ca(1), and one Sb(2) atom to form a mixture of edge and corner-sharing OCa3Sb tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Sb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.317
_cell_length_b   7.317
_cell_length_c   7.317
_cell_angle_alpha   119.998
_cell_angle_beta   118.460
_cell_angle_gamma   91.346
_symmetry_Int_Tables_number   1
_cell_volume   280.139
_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  0.000  0.000  0.500  1.0
  Ca  Ca1  1  1.000  0.500  1.000  1.0
  Ca  Ca2  1  0.000  0.000  0.000  1.0
  Ca  Ca3  1  0.500  0.500  1.000  1.0
  Sb  Sb4  1  0.500  0.000  1.000  1.0
  Sb  Sb5  1  0.500  0.500  0.500  1.0
  Sb  Sb6  1  0.500  1.000  0.500  1.0
  Sb  Sb7  1  1.000  0.500  0.500  1.0
  O  O8  1  0.445  0.090  0.772  1.0
  O  O9  1  0.555  0.327  0.645  1.0
  O  O10  1  0.182  0.410  0.355  1.0
  O  O11  1  0.818  0.173  0.228  1.0
  O  O12  1  0.555  0.910  0.228  1.0
  O  O13  1  0.445  0.673  0.355  1.0
  O  O14  1  0.818  0.590  0.645  1.0
  O  O15  1  0.182  0.827  0.772  1.0
  O  O16  1  0.597  0.750  0.847  1.0
  O  O17  1  0.403  0.250  0.153  1.0
  O  O18  1  0.178  0.906  0.272  1.0
  O  O19  1  0.822  0.094  0.728  1.0
  O  O20  1  0.865  0.594  0.272  1.0
  O  O21  1  0.135  0.406  0.728  1.0
[/CIF]
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The crystal structure described by Ca2Sb2O7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. In the second Ca site, Ca(2) is bonded to two equivalent O(2), two equivalent O(3), and four equivalent O(1) atoms to form distorted CaO8 hexagonal bipyramids that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with two equivalent Sb(2)O6 octahedra, edges with two equivalent Sb(2)O6 octahedra, and edges with four equivalent Sb(1)O6 octahedra. The corner-sharing octahedral tilt angles are 55°. There are two inequivalent Sb sites. In the first Sb site, Sb(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Sb(1)O6 octahedra, corners with four equivalent Sb(2)O6 octahedra, and edges with four equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-46°. In the second Sb site, Sb(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form SbO6 octahedra that share corners with two equivalent Ca(2)O8 hexagonal bipyramids, corners with four equivalent Sb(1)O6 octahedra, and edges with two equivalent Ca(2)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 46°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Ca(1), one Ca(2), one Sb(1), and one Sb(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(2) and two equivalent Sb(1) atoms. In the third O site, O(3) is bonded to one Ca(2), two equivalent Ca(1), and one Sb(2) atom to form a mixture of edge and corner-sharing OCa3Sb tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Sb2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.317
_cell_length_b   7.317
_cell_length_c   7.317
_cell_angle_alpha   119.998
_cell_angle_beta   118.460
_cell_angle_gamma   91.346
_symmetry_Int_Tables_number   1
_cell_volume   280.139
_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  0.000  0.000  0.500  1.0
  Ca  Ca1  1  1.000  0.500  1.000  1.0
  Ca  Ca2  1  0.000  0.000  0.000  1.0
  Ca  Ca3  1  0.500  0.500  1.000  1.0
  Sb  Sb4  1  0.500  0.000  1.000  1.0
  Sb  Sb5  1  0.500  0.500  0.500  1.0
  Sb  Sb6  1  0.500  1.000  0.500  1.0
  Sb  Sb7  1  1.000  0.500  0.500  1.0
  O  O8  1  0.445  0.090  0.772  1.0
  O  O9  1  0.555  0.327  0.645  1.0
  O  O10  1  0.182  0.410  0.355  1.0
  O  O11  1  0.818  0.173  0.228  1.0
  O  O12  1  0.555  0.910  0.228  1.0
  O  O13  1  0.445  0.673  0.355  1.0
  O  O14  1  0.818  0.590  0.645  1.0
  O  O15  1  0.182  0.827  0.772  1.0
  O  O16  1  0.597  0.750  0.847  1.0
  O  O17  1  0.403  0.250  0.153  1.0
  O  O18  1  0.178  0.906  0.272  1.0
  O  O19  1  0.822  0.094  0.728  1.0
  O  O20  1  0.865  0.594  0.272  1.0
  O  O21  1  0.135  0.406  0.728  1.0
[/CIF]
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