The structure described by CaW4O9 crystallizes in the tetragonal P4/n space group. Ca(1) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(3) atoms. W(1) is bonded to one O(1), two equivalent O(2), and three equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 9-25°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a square co-planar geometry to four equivalent W(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1) and two equivalent W(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1) and three equivalent W(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaW4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.707
_cell_length_b   9.707
_cell_length_c   3.978
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   374.803
_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  0.500  0.088  1.0
  Ca  Ca1  1  0.500  0.000  0.912  1.0
  W  W2  1  0.091  0.789  0.545  1.0
  W  W3  1  0.211  0.091  0.455  1.0
  W  W4  1  0.711  0.591  0.545  1.0
  W  W5  1  0.591  0.289  0.455  1.0
  W  W6  1  0.909  0.211  0.545  1.0
  W  W7  1  0.289  0.409  0.545  1.0
  W  W8  1  0.409  0.711  0.455  1.0
  W  W9  1  0.789  0.909  0.455  1.0
  O  O10  1  0.000  0.000  0.500  1.0
  O  O11  1  0.500  0.500  0.500  1.0
  O  O12  1  0.748  0.925  0.963  1.0
  O  O13  1  0.425  0.752  0.963  1.0
  O  O14  1  0.575  0.248  0.963  1.0
  O  O15  1  0.252  0.075  0.963  1.0
  O  O16  1  0.752  0.575  0.037  1.0
  O  O17  1  0.075  0.748  0.037  1.0
  O  O18  1  0.925  0.252  0.037  1.0
  O  O19  1  0.248  0.425  0.037  1.0
  O  O20  1  0.114  0.278  0.520  1.0
  O  O21  1  0.778  0.386  0.520  1.0
  O  O22  1  0.222  0.614  0.520  1.0
  O  O23  1  0.886  0.722  0.520  1.0
  O  O24  1  0.614  0.778  0.480  1.0
  O  O25  1  0.722  0.114  0.480  1.0
  O  O26  1  0.278  0.886  0.480  1.0
  O  O27  1  0.386  0.222  0.480  1.0
[/CIF]
.
The structure described by CaW4O9 crystallizes in the tetragonal P4/n space group. Ca(1) is bonded in a distorted square co-planar geometry to four equivalent O(2) and four equivalent O(3) atoms. W(1) is bonded to one O(1), two equivalent O(2), and three equivalent O(3) atoms to form a mixture of distorted corner and edge-sharing WO6 octahedra. The corner-sharing octahedral tilt angles range from 9-25°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a square co-planar geometry to four equivalent W(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1) and two equivalent W(1) atoms. In the third O site, O(3) is bonded in a 3-coordinate geometry to one Ca(1) and three equivalent W(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_CaW4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.707
_cell_length_b   9.707
_cell_length_c   3.978
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   374.803
_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  0.500  0.088  1.0
  Ca  Ca1  1  0.500  0.000  0.912  1.0
  W  W2  1  0.091  0.789  0.545  1.0
  W  W3  1  0.211  0.091  0.455  1.0
  W  W4  1  0.711  0.591  0.545  1.0
  W  W5  1  0.591  0.289  0.455  1.0
  W  W6  1  0.909  0.211  0.545  1.0
  W  W7  1  0.289  0.409  0.545  1.0
  W  W8  1  0.409  0.711  0.455  1.0
  W  W9  1  0.789  0.909  0.455  1.0
  O  O10  1  0.000  0.000  0.500  1.0
  O  O11  1  0.500  0.500  0.500  1.0
  O  O12  1  0.748  0.925  0.963  1.0
  O  O13  1  0.425  0.752  0.963  1.0
  O  O14  1  0.575  0.248  0.963  1.0
  O  O15  1  0.252  0.075  0.963  1.0
  O  O16  1  0.752  0.575  0.037  1.0
  O  O17  1  0.075  0.748  0.037  1.0
  O  O18  1  0.925  0.252  0.037  1.0
  O  O19  1  0.248  0.425  0.037  1.0
  O  O20  1  0.114  0.278  0.520  1.0
  O  O21  1  0.778  0.386  0.520  1.0
  O  O22  1  0.222  0.614  0.520  1.0
  O  O23  1  0.886  0.722  0.520  1.0
  O  O24  1  0.614  0.778  0.480  1.0
  O  O25  1  0.722  0.114  0.480  1.0
  O  O26  1  0.278  0.886  0.480  1.0
  O  O27  1  0.386  0.222  0.480  1.0
[/CIF]
.