The material described by Ca2Os2O7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) 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(1)O8 hexagonal bipyramids, corners with two equivalent Os(2)O6 octahedra, edges with two equivalent Os(2)O6 octahedra, and edges with four equivalent Os(1)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. In the second Ca site, Ca(2) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. There are two inequivalent Os sites. In the first Os site, Os(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form OsO6 octahedra that share corners with two equivalent Os(1)O6 octahedra, corners with four equivalent Os(2)O6 octahedra, and edges with four equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-45°. In the second Os site, Os(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form OsO6 octahedra that share corners with two equivalent Ca(1)O8 hexagonal bipyramids, corners with four equivalent Os(1)O6 octahedra, and edges with two equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. 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 Os(1), and one Os(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Os(1) atoms. In the third O site, O(3) is bonded to one Ca(1), two equivalent Ca(2), and one Os(2) atom to form a mixture of corner and edge-sharing OCa3Os tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Os2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.257
_cell_length_b   7.257
_cell_length_c   7.257
_cell_angle_alpha   120.421
_cell_angle_beta   118.392
_cell_angle_gamma   91.046
_symmetry_Int_Tables_number   1
_cell_volume   272.494
_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  0.500  0.500  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.000  1.0
  Ca  Ca2  1  0.500  0.500  0.500  1.0
  Ca  Ca3  1  0.500  0.000  0.000  1.0
  Os  Os4  1  0.000  0.500  0.000  1.0
  Os  Os5  1  0.000  0.000  0.500  1.0
  Os  Os6  1  0.000  0.500  0.500  1.0
  Os  Os7  1  0.500  0.000  0.500  1.0
  O  O8  1  0.948  0.584  0.768  1.0
  O  O9  1  0.052  0.821  0.637  1.0
  O  O10  1  0.684  0.916  0.364  1.0
  O  O11  1  0.316  0.679  0.232  1.0
  O  O12  1  0.052  0.416  0.232  1.0
  O  O13  1  0.948  0.179  0.363  1.0
  O  O14  1  0.316  0.084  0.636  1.0
  O  O15  1  0.684  0.321  0.768  1.0
  O  O16  1  0.100  0.250  0.850  1.0
  O  O17  1  0.900  0.750  0.150  1.0
  O  O18  1  0.365  0.096  0.269  1.0
  O  O19  1  0.635  0.904  0.731  1.0
  O  O20  1  0.674  0.404  0.269  1.0
  O  O21  1  0.326  0.596  0.731  1.0
[/CIF]
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The material described by Ca2Os2O7 crystallizes in the orthorhombic Imma space group. There are two inequivalent Ca sites. In the first Ca site, Ca(1) 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(1)O8 hexagonal bipyramids, corners with two equivalent Os(2)O6 octahedra, edges with two equivalent Os(2)O6 octahedra, and edges with four equivalent Os(1)O6 octahedra. The corner-sharing octahedral tilt angles are 56°. In the second Ca site, Ca(2) is bonded in a distorted body-centered cubic geometry to four equivalent O(1) and four equivalent O(3) atoms. There are two inequivalent Os sites. In the first Os site, Os(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form OsO6 octahedra that share corners with two equivalent Os(1)O6 octahedra, corners with four equivalent Os(2)O6 octahedra, and edges with four equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 43-45°. In the second Os site, Os(2) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form OsO6 octahedra that share corners with two equivalent Ca(1)O8 hexagonal bipyramids, corners with four equivalent Os(1)O6 octahedra, and edges with two equivalent Ca(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 43°. 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 Os(1), and one Os(2) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to two equivalent Ca(1) and two equivalent Os(1) atoms. In the third O site, O(3) is bonded to one Ca(1), two equivalent Ca(2), and one Os(2) atom to form a mixture of corner and edge-sharing OCa3Os tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2Os2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.257
_cell_length_b   7.257
_cell_length_c   7.257
_cell_angle_alpha   120.421
_cell_angle_beta   118.392
_cell_angle_gamma   91.046
_symmetry_Int_Tables_number   1
_cell_volume   272.494
_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  0.500  0.500  0.000  1.0
  Ca  Ca1  1  0.000  0.000  0.000  1.0
  Ca  Ca2  1  0.500  0.500  0.500  1.0
  Ca  Ca3  1  0.500  0.000  0.000  1.0
  Os  Os4  1  0.000  0.500  0.000  1.0
  Os  Os5  1  0.000  0.000  0.500  1.0
  Os  Os6  1  0.000  0.500  0.500  1.0
  Os  Os7  1  0.500  0.000  0.500  1.0
  O  O8  1  0.948  0.584  0.768  1.0
  O  O9  1  0.052  0.821  0.637  1.0
  O  O10  1  0.684  0.916  0.364  1.0
  O  O11  1  0.316  0.679  0.232  1.0
  O  O12  1  0.052  0.416  0.232  1.0
  O  O13  1  0.948  0.179  0.363  1.0
  O  O14  1  0.316  0.084  0.636  1.0
  O  O15  1  0.684  0.321  0.768  1.0
  O  O16  1  0.100  0.250  0.850  1.0
  O  O17  1  0.900  0.750  0.150  1.0
  O  O18  1  0.365  0.096  0.269  1.0
  O  O19  1  0.635  0.904  0.731  1.0
  O  O20  1  0.674  0.404  0.269  1.0
  O  O21  1  0.326  0.596  0.731  1.0
[/CIF]
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