The material structure described by CaAlFSiO4 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 7-coordinate geometry to two equivalent O(2), four equivalent O(1), and one F(1) atom. Al(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent F(1) atoms to form AlO4F2 octahedra that share corners with two equivalent Al(1)O4F2 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with four equivalent Al(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 35-52°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one Al(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1), one Al(1), and one Si(1) atom. F(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_CaAlSiO4F
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.391
_cell_length_b   5.391
_cell_length_c   7.039
_cell_angle_alpha   75.095
_cell_angle_beta   75.095
_cell_angle_gamma   105.486
_symmetry_Int_Tables_number   1
_cell_volume   178.462
_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  0.836  0.164  0.750  1.0
  Ca  Ca1  1  0.164  0.836  0.250  1.0
  Al  Al2  1  0.500  0.500  0.000  1.0
  Al  Al3  1  0.500  0.500  0.500  1.0
  Si  Si4  1  0.185  0.815  0.750  1.0
  Si  Si5  1  0.815  0.185  0.250  1.0
  O  O6  1  0.198  0.609  0.611  1.0
  O  O7  1  0.391  0.802  0.889  1.0
  O  O8  1  0.802  0.391  0.389  1.0
  O  O9  1  0.609  0.198  0.111  1.0
  O  O10  1  0.261  0.132  0.595  1.0
  O  O11  1  0.739  0.868  0.405  1.0
  O  O12  1  0.868  0.739  0.905  1.0
  O  O13  1  0.132  0.261  0.095  1.0
  F  F14  1  0.568  0.432  0.750  1.0
  F  F15  1  0.432  0.568  0.250  1.0
[/CIF]
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The material structure described by CaAlFSiO4 crystallizes in the monoclinic C2/c space group. Ca(1) is bonded in a 7-coordinate geometry to two equivalent O(2), four equivalent O(1), and one F(1) atom. Al(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent F(1) atoms to form AlO4F2 octahedra that share corners with two equivalent Al(1)O4F2 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. Si(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with four equivalent Al(1)O4F2 octahedra. The corner-sharing octahedral tilt angles range from 35-52°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one Al(1), and one Si(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Ca(1), one Al(1), and one Si(1) atom. F(1) is bonded in a distorted trigonal planar geometry to one Ca(1) and two equivalent Al(1) atoms. is represented by the CIF file [CIF]
data_CaAlSiO4F
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.391
_cell_length_b   5.391
_cell_length_c   7.039
_cell_angle_alpha   75.095
_cell_angle_beta   75.095
_cell_angle_gamma   105.486
_symmetry_Int_Tables_number   1
_cell_volume   178.462
_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  0.836  0.164  0.750  1.0
  Ca  Ca1  1  0.164  0.836  0.250  1.0
  Al  Al2  1  0.500  0.500  0.000  1.0
  Al  Al3  1  0.500  0.500  0.500  1.0
  Si  Si4  1  0.185  0.815  0.750  1.0
  Si  Si5  1  0.815  0.185  0.250  1.0
  O  O6  1  0.198  0.609  0.611  1.0
  O  O7  1  0.391  0.802  0.889  1.0
  O  O8  1  0.802  0.391  0.389  1.0
  O  O9  1  0.609  0.198  0.111  1.0
  O  O10  1  0.261  0.132  0.595  1.0
  O  O11  1  0.739  0.868  0.405  1.0
  O  O12  1  0.868  0.739  0.905  1.0
  O  O13  1  0.132  0.261  0.095  1.0
  F  F14  1  0.568  0.432  0.750  1.0
  F  F15  1  0.432  0.568  0.250  1.0
[/CIF]
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