The material described by Y4TiSi2(O3F2)3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(2), one O(4), one F(3), and four equivalent F(1) atoms to form YO2F5 pentagonal bipyramids that share  a cornercorner with one Y(1)O2F5 pentagonal bipyramid, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Y(1)O2F5 pentagonal bipyramids. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), two equivalent O(1), one F(2), and two equivalent F(1) atoms. Ti(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Y(1)O2F5 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 57°. There are four inequivalent O sites. In the first O site, O(4) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(2), and one Si(1) atom. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one Y(2), one Ti(1), and one Si(1) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(2), and one Si(1) atom. In the fourth O site, O(3) is bonded to two equivalent Y(2) and two equivalent Ti(1) atoms to form distorted corner-sharing OY2Ti2 tetrahedra. There are three inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Y(2) and two equivalent Y(1) atoms. In the second F site, F(2) is bonded in a bent 120 degrees geometry to two equivalent Y(2) atoms. In the third F site, F(3) is bonded in a linear geometry to two equivalent Y(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y4TiSi2(O3F2)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.229
_cell_length_b   9.229
_cell_length_c   7.125
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   109.111
_symmetry_Int_Tables_number   1
_cell_volume   573.432
_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
  Y  Y0  1  0.582  0.289  0.250  1.0
  Y  Y1  1  0.076  0.337  0.750  1.0
  Y  Y2  1  0.289  0.582  0.250  1.0
  Y  Y3  1  0.418  0.711  0.750  1.0
  Y  Y4  1  0.337  0.076  0.750  1.0
  Y  Y5  1  0.663  0.924  0.250  1.0
  Y  Y6  1  0.711  0.418  0.750  1.0
  Y  Y7  1  0.924  0.663  0.250  1.0
  Ti  Ti8  1  0.000  0.000  0.500  1.0
  Ti  Ti9  1  0.000  0.000  0.000  1.0
  Si  Si10  1  0.277  0.964  0.250  1.0
  Si  Si11  1  0.723  0.036  0.750  1.0
  Si  Si12  1  0.964  0.277  0.250  1.0
  Si  Si13  1  0.036  0.723  0.750  1.0
  O  O14  1  0.221  0.032  0.443  1.0
  O  O15  1  0.029  0.466  0.250  1.0
  O  O16  1  0.062  0.062  0.750  1.0
  O  O17  1  0.971  0.534  0.750  1.0
  O  O18  1  0.806  0.223  0.750  1.0
  O  O19  1  0.779  0.968  0.943  1.0
  O  O20  1  0.223  0.806  0.750  1.0
  O  O21  1  0.221  0.032  0.057  1.0
  O  O22  1  0.032  0.221  0.443  1.0
  O  O23  1  0.968  0.779  0.557  1.0
  O  O24  1  0.032  0.221  0.057  1.0
  O  O25  1  0.534  0.971  0.750  1.0
  O  O26  1  0.968  0.779  0.943  1.0
  O  O27  1  0.466  0.029  0.250  1.0
  O  O28  1  0.194  0.777  0.250  1.0
  O  O29  1  0.779  0.968  0.557  1.0
  O  O30  1  0.777  0.194  0.250  1.0
  O  O31  1  0.938  0.938  0.250  1.0
  F  F32  1  0.245  0.529  0.939  1.0
  F  F33  1  0.755  0.471  0.439  1.0
  F  F34  1  0.699  0.699  0.250  1.0
  F  F35  1  0.584  0.584  0.750  1.0
  F  F36  1  0.301  0.301  0.750  1.0
  F  F37  1  0.755  0.471  0.061  1.0
  F  F38  1  0.416  0.416  0.250  1.0
  F  F39  1  0.529  0.245  0.939  1.0
  F  F40  1  0.471  0.755  0.061  1.0
  F  F41  1  0.245  0.529  0.561  1.0
  F  F42  1  0.471  0.755  0.439  1.0
  F  F43  1  0.529  0.245  0.561  1.0
[/CIF]
.
The material described by Y4TiSi2(O3F2)3 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent Y sites. In the first Y site, Y(1) is bonded to one O(2), one O(4), one F(3), and four equivalent F(1) atoms to form YO2F5 pentagonal bipyramids that share  a cornercorner with one Y(1)O2F5 pentagonal bipyramid, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Y(1)O2F5 pentagonal bipyramids. In the second Y site, Y(2) is bonded in a 8-coordinate geometry to one O(2), one O(3), one O(4), two equivalent O(1), one F(2), and two equivalent F(1) atoms. Ti(1) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with four equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(1)O6 octahedra and corners with two equivalent Y(1)O2F5 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 57°. There are four inequivalent O sites. In the first O site, O(4) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(2), and one Si(1) atom. In the second O site, O(1) is bonded in a distorted trigonal planar geometry to one Y(2), one Ti(1), and one Si(1) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Y(1), one Y(2), and one Si(1) atom. In the fourth O site, O(3) is bonded to two equivalent Y(2) and two equivalent Ti(1) atoms to form distorted corner-sharing OY2Ti2 tetrahedra. There are three inequivalent F sites. In the first F site, F(1) is bonded in a trigonal planar geometry to one Y(2) and two equivalent Y(1) atoms. In the second F site, F(2) is bonded in a bent 120 degrees geometry to two equivalent Y(2) atoms. In the third F site, F(3) is bonded in a linear geometry to two equivalent Y(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Y4TiSi2(O3F2)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.229
_cell_length_b   9.229
_cell_length_c   7.125
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   109.111
_symmetry_Int_Tables_number   1
_cell_volume   573.432
_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
  Y  Y0  1  0.582  0.289  0.250  1.0
  Y  Y1  1  0.076  0.337  0.750  1.0
  Y  Y2  1  0.289  0.582  0.250  1.0
  Y  Y3  1  0.418  0.711  0.750  1.0
  Y  Y4  1  0.337  0.076  0.750  1.0
  Y  Y5  1  0.663  0.924  0.250  1.0
  Y  Y6  1  0.711  0.418  0.750  1.0
  Y  Y7  1  0.924  0.663  0.250  1.0
  Ti  Ti8  1  0.000  0.000  0.500  1.0
  Ti  Ti9  1  0.000  0.000  0.000  1.0
  Si  Si10  1  0.277  0.964  0.250  1.0
  Si  Si11  1  0.723  0.036  0.750  1.0
  Si  Si12  1  0.964  0.277  0.250  1.0
  Si  Si13  1  0.036  0.723  0.750  1.0
  O  O14  1  0.221  0.032  0.443  1.0
  O  O15  1  0.029  0.466  0.250  1.0
  O  O16  1  0.062  0.062  0.750  1.0
  O  O17  1  0.971  0.534  0.750  1.0
  O  O18  1  0.806  0.223  0.750  1.0
  O  O19  1  0.779  0.968  0.943  1.0
  O  O20  1  0.223  0.806  0.750  1.0
  O  O21  1  0.221  0.032  0.057  1.0
  O  O22  1  0.032  0.221  0.443  1.0
  O  O23  1  0.968  0.779  0.557  1.0
  O  O24  1  0.032  0.221  0.057  1.0
  O  O25  1  0.534  0.971  0.750  1.0
  O  O26  1  0.968  0.779  0.943  1.0
  O  O27  1  0.466  0.029  0.250  1.0
  O  O28  1  0.194  0.777  0.250  1.0
  O  O29  1  0.779  0.968  0.557  1.0
  O  O30  1  0.777  0.194  0.250  1.0
  O  O31  1  0.938  0.938  0.250  1.0
  F  F32  1  0.245  0.529  0.939  1.0
  F  F33  1  0.755  0.471  0.439  1.0
  F  F34  1  0.699  0.699  0.250  1.0
  F  F35  1  0.584  0.584  0.750  1.0
  F  F36  1  0.301  0.301  0.750  1.0
  F  F37  1  0.755  0.471  0.061  1.0
  F  F38  1  0.416  0.416  0.250  1.0
  F  F39  1  0.529  0.245  0.939  1.0
  F  F40  1  0.471  0.755  0.061  1.0
  F  F41  1  0.245  0.529  0.561  1.0
  F  F42  1  0.471  0.755  0.439  1.0
  F  F43  1  0.529  0.245  0.561  1.0
[/CIF]
.