The structure described by Ti4Pb2O9F2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(5), two equivalent O(1), and one F(1) atom to form distorted TiO5F octahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with three equivalent Ti(1)O5F octahedra, and edges with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-29°. In the second Ti site, Ti(2) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O5F octahedra, corners with two equivalent Ti(2)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra, and edges with two equivalent Ti(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 17-18°. Pb(1) is bonded in a 5-coordinate geometry to two equivalent O(4) and three equivalent F(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Ti(2) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a T-shaped geometry to one Ti(1) and two equivalent Ti(2) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ti(2) and two equivalent Pb(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ti(1) and one Ti(2) atom. F(1) is bonded to one Ti(1) and three equivalent Pb(1) atoms to form a mixture of edge and corner-sharing FTiPb3 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ti4Pb2O9F2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.754
_cell_length_b   7.754
_cell_length_c   10.496
_cell_angle_alpha   48.143
_cell_angle_beta   48.143
_cell_angle_gamma   28.700
_symmetry_Int_Tables_number   1
_cell_volume   219.698
_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
  Ti  Ti0  1  0.658  0.658  0.773  1.0
  Ti  Ti1  1  0.342  0.342  0.227  1.0
  Ti  Ti2  1  0.621  0.621  0.453  1.0
  Ti  Ti3  1  0.379  0.379  0.547  1.0
  Pb  Pb4  1  0.085  0.085  0.164  1.0
  Pb  Pb5  1  0.915  0.915  0.836  1.0
  O  O6  1  0.198  0.198  0.755  1.0
  O  O7  1  0.802  0.802  0.245  1.0
  O  O8  1  0.852  0.852  0.568  1.0
  O  O9  1  0.148  0.148  0.432  1.0
  O  O10  1  0.500  0.500  0.000  1.0
  O  O11  1  0.437  0.437  0.662  1.0
  O  O12  1  0.563  0.563  0.338  1.0
  O  O13  1  0.615  0.615  0.652  1.0
  O  O14  1  0.385  0.385  0.348  1.0
  F  F15  1  0.712  0.712  0.938  1.0
  F  F16  1  0.288  0.288  0.062  1.0
[/CIF]
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The structure described by Ti4Pb2O9F2 crystallizes in the monoclinic C2/m space group. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(2), one O(3), one O(5), two equivalent O(1), and one F(1) atom to form distorted TiO5F octahedra that share  a cornercorner with one Ti(2)O6 octahedra, corners with three equivalent Ti(1)O5F octahedra, and edges with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-29°. In the second Ti site, Ti(2) is bonded to one O(1), one O(5), two equivalent O(2), and two equivalent O(4) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O5F octahedra, corners with two equivalent Ti(2)O6 octahedra,  an edgeedge with one Ti(2)O6 octahedra, and edges with two equivalent Ti(1)O5F octahedra. The corner-sharing octahedral tilt angles range from 17-18°. Pb(1) is bonded in a 5-coordinate geometry to two equivalent O(4) and three equivalent F(1) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Ti(2) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a T-shaped geometry to one Ti(1) and two equivalent Ti(2) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ti(1) atoms. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ti(2) and two equivalent Pb(1) atoms. In the fifth O site, O(5) is bonded in a distorted linear geometry to one Ti(1) and one Ti(2) atom. F(1) is bonded to one Ti(1) and three equivalent Pb(1) atoms to form a mixture of edge and corner-sharing FTiPb3 tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ti4Pb2O9F2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.754
_cell_length_b   7.754
_cell_length_c   10.496
_cell_angle_alpha   48.143
_cell_angle_beta   48.143
_cell_angle_gamma   28.700
_symmetry_Int_Tables_number   1
_cell_volume   219.698
_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
  Ti  Ti0  1  0.658  0.658  0.773  1.0
  Ti  Ti1  1  0.342  0.342  0.227  1.0
  Ti  Ti2  1  0.621  0.621  0.453  1.0
  Ti  Ti3  1  0.379  0.379  0.547  1.0
  Pb  Pb4  1  0.085  0.085  0.164  1.0
  Pb  Pb5  1  0.915  0.915  0.836  1.0
  O  O6  1  0.198  0.198  0.755  1.0
  O  O7  1  0.802  0.802  0.245  1.0
  O  O8  1  0.852  0.852  0.568  1.0
  O  O9  1  0.148  0.148  0.432  1.0
  O  O10  1  0.500  0.500  0.000  1.0
  O  O11  1  0.437  0.437  0.662  1.0
  O  O12  1  0.563  0.563  0.338  1.0
  O  O13  1  0.615  0.615  0.652  1.0
  O  O14  1  0.385  0.385  0.348  1.0
  F  F15  1  0.712  0.712  0.938  1.0
  F  F16  1  0.288  0.288  0.062  1.0
[/CIF]
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