The material described by Ca2As2O7 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted CaO6 octahedra that share corners with six equivalent As(1)O4 tetrahedra and edges with three equivalent Ca(1)O6 octahedra. As(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form AsO4 tetrahedra that share corners with six equivalent Ca(1)O6 octahedra and  a cornercorner with one As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-60°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one As(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent As(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one As(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2As2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.926
_cell_length_b   5.862
_cell_length_c   5.862
_cell_angle_alpha   105.851
_cell_angle_beta   96.859
_cell_angle_gamma   96.859
_symmetry_Int_Tables_number   1
_cell_volume   159.633
_cell_formula_units_Z   1
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  0.693  0.307  1.0
  Ca  Ca1  1  0.500  0.307  0.693  1.0
  As  As2  1  0.091  0.774  0.774  1.0
  As  As3  1  0.909  0.226  0.226  1.0
  O  O4  1  0.277  0.916  0.616  1.0
  O  O5  1  0.723  0.384  0.084  1.0
  O  O6  1  0.723  0.084  0.384  1.0
  O  O7  1  0.277  0.616  0.916  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.786  0.618  0.618  1.0
  O  O10  1  0.214  0.382  0.382  1.0
[/CIF]
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The material described by Ca2As2O7 crystallizes in the monoclinic C2/m space group. Ca(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form distorted CaO6 octahedra that share corners with six equivalent As(1)O4 tetrahedra and edges with three equivalent Ca(1)O6 octahedra. As(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form AsO4 tetrahedra that share corners with six equivalent Ca(1)O6 octahedra and  a cornercorner with one As(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 46-60°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one As(1) atom. In the second O site, O(2) is bonded in a linear geometry to two equivalent As(1) atoms. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ca(1) and one As(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ca2As2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.926
_cell_length_b   5.862
_cell_length_c   5.862
_cell_angle_alpha   105.851
_cell_angle_beta   96.859
_cell_angle_gamma   96.859
_symmetry_Int_Tables_number   1
_cell_volume   159.633
_cell_formula_units_Z   1
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  0.693  0.307  1.0
  Ca  Ca1  1  0.500  0.307  0.693  1.0
  As  As2  1  0.091  0.774  0.774  1.0
  As  As3  1  0.909  0.226  0.226  1.0
  O  O4  1  0.277  0.916  0.616  1.0
  O  O5  1  0.723  0.384  0.084  1.0
  O  O6  1  0.723  0.084  0.384  1.0
  O  O7  1  0.277  0.616  0.916  1.0
  O  O8  1  0.000  0.000  0.000  1.0
  O  O9  1  0.786  0.618  0.618  1.0
  O  O10  1  0.214  0.382  0.382  1.0
[/CIF]
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