The material described by Na4Ti2(SiO4)3 crystallizes in the trigonal R-3c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. Ti(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form TiO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. 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 Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-37°. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Na(2), two equivalent Na(1), one Ti(1), and one Si(1) atom to form a mixture of distorted corner, edge, and face-sharing ONa3TiSi trigonal bipyramids. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ti(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na4Ti2(SiO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.950
_cell_length_b   8.950
_cell_length_c   8.950
_cell_angle_alpha   60.370
_cell_angle_beta   60.370
_cell_angle_gamma   60.370
_symmetry_Int_Tables_number   1
_cell_volume   511.133
_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
  Na  Na0  1  0.878  0.622  0.250  1.0
  Na  Na1  1  0.622  0.250  0.878  1.0
  Na  Na2  1  0.250  0.878  0.622  1.0
  Na  Na3  1  0.378  0.750  0.122  1.0
  Na  Na4  1  0.750  0.122  0.378  1.0
  Na  Na5  1  0.122  0.378  0.750  1.0
  Na  Na6  1  0.500  0.500  0.500  1.0
  Na  Na7  1  0.000  0.000  0.000  1.0
  O  O8  1  0.506  0.143  0.281  1.0
  O  O9  1  0.143  0.281  0.506  1.0
  O  O10  1  0.281  0.506  0.143  1.0
  O  O11  1  0.006  0.781  0.643  1.0
  O  O12  1  0.781  0.643  0.006  1.0
  O  O13  1  0.643  0.006  0.781  1.0
  O  O14  1  0.494  0.857  0.719  1.0
  O  O15  1  0.857  0.719  0.494  1.0
  O  O16  1  0.719  0.494  0.857  1.0
  O  O17  1  0.994  0.219  0.357  1.0
  O  O18  1  0.219  0.357  0.994  1.0
  O  O19  1  0.357  0.994  0.219  1.0
  O  O20  1  0.440  0.225  0.575  1.0
  O  O21  1  0.225  0.575  0.440  1.0
  O  O22  1  0.575  0.440  0.225  1.0
  O  O23  1  0.940  0.075  0.725  1.0
  O  O24  1  0.075  0.725  0.940  1.0
  O  O25  1  0.725  0.940  0.075  1.0
  O  O26  1  0.560  0.775  0.425  1.0
  O  O27  1  0.775  0.425  0.560  1.0
  O  O28  1  0.425  0.560  0.775  1.0
  O  O29  1  0.060  0.925  0.275  1.0
  O  O30  1  0.925  0.275  0.060  1.0
  O  O31  1  0.275  0.060  0.925  1.0
  Si  Si32  1  0.539  0.961  0.250  1.0
  Si  Si33  1  0.961  0.250  0.539  1.0
  Si  Si34  1  0.250  0.539  0.961  1.0
  Si  Si35  1  0.039  0.750  0.461  1.0
  Si  Si36  1  0.750  0.461  0.039  1.0
  Si  Si37  1  0.461  0.039  0.750  1.0
  Ti  Ti38  1  0.353  0.353  0.353  1.0
  Ti  Ti39  1  0.853  0.853  0.853  1.0
  Ti  Ti40  1  0.647  0.647  0.647  1.0
  Ti  Ti41  1  0.147  0.147  0.147  1.0
[/CIF]
.
The material described by Na4Ti2(SiO4)3 crystallizes in the trigonal R-3c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(2) atoms. In the second Na site, Na(2) is bonded in a distorted hexagonal planar geometry to six equivalent O(2) atoms. Ti(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form TiO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra. 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 Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-37°. There are two inequivalent O sites. In the first O site, O(2) is bonded to one Na(2), two equivalent Na(1), one Ti(1), and one Si(1) atom to form a mixture of distorted corner, edge, and face-sharing ONa3TiSi trigonal bipyramids. In the second O site, O(1) is bonded in a distorted bent 150 degrees geometry to one Na(1), one Ti(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Na4Ti2(SiO4)3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.950
_cell_length_b   8.950
_cell_length_c   8.950
_cell_angle_alpha   60.370
_cell_angle_beta   60.370
_cell_angle_gamma   60.370
_symmetry_Int_Tables_number   1
_cell_volume   511.133
_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
  Na  Na0  1  0.878  0.622  0.250  1.0
  Na  Na1  1  0.622  0.250  0.878  1.0
  Na  Na2  1  0.250  0.878  0.622  1.0
  Na  Na3  1  0.378  0.750  0.122  1.0
  Na  Na4  1  0.750  0.122  0.378  1.0
  Na  Na5  1  0.122  0.378  0.750  1.0
  Na  Na6  1  0.500  0.500  0.500  1.0
  Na  Na7  1  0.000  0.000  0.000  1.0
  O  O8  1  0.506  0.143  0.281  1.0
  O  O9  1  0.143  0.281  0.506  1.0
  O  O10  1  0.281  0.506  0.143  1.0
  O  O11  1  0.006  0.781  0.643  1.0
  O  O12  1  0.781  0.643  0.006  1.0
  O  O13  1  0.643  0.006  0.781  1.0
  O  O14  1  0.494  0.857  0.719  1.0
  O  O15  1  0.857  0.719  0.494  1.0
  O  O16  1  0.719  0.494  0.857  1.0
  O  O17  1  0.994  0.219  0.357  1.0
  O  O18  1  0.219  0.357  0.994  1.0
  O  O19  1  0.357  0.994  0.219  1.0
  O  O20  1  0.440  0.225  0.575  1.0
  O  O21  1  0.225  0.575  0.440  1.0
  O  O22  1  0.575  0.440  0.225  1.0
  O  O23  1  0.940  0.075  0.725  1.0
  O  O24  1  0.075  0.725  0.940  1.0
  O  O25  1  0.725  0.940  0.075  1.0
  O  O26  1  0.560  0.775  0.425  1.0
  O  O27  1  0.775  0.425  0.560  1.0
  O  O28  1  0.425  0.560  0.775  1.0
  O  O29  1  0.060  0.925  0.275  1.0
  O  O30  1  0.925  0.275  0.060  1.0
  O  O31  1  0.275  0.060  0.925  1.0
  Si  Si32  1  0.539  0.961  0.250  1.0
  Si  Si33  1  0.961  0.250  0.539  1.0
  Si  Si34  1  0.250  0.539  0.961  1.0
  Si  Si35  1  0.039  0.750  0.461  1.0
  Si  Si36  1  0.750  0.461  0.039  1.0
  Si  Si37  1  0.461  0.039  0.750  1.0
  Ti  Ti38  1  0.353  0.353  0.353  1.0
  Ti  Ti39  1  0.853  0.853  0.853  1.0
  Ti  Ti40  1  0.647  0.647  0.647  1.0
  Ti  Ti41  1  0.147  0.147  0.147  1.0
[/CIF]
.