The crystal structure described by Ba4Ti6Si4O25 crystallizes in the monoclinic P2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 11-coordinate geometry to one O(10), one O(12), one O(2), one O(3), one O(5), two equivalent O(1), two equivalent O(4), and two equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(10), one O(11), one O(2), one O(3), one O(6), two equivalent O(13), two equivalent O(8), and two equivalent O(9) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(12), two equivalent O(2), and two equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. In the second Ti site, Ti(2) is bonded to two equivalent O(12), two equivalent O(3), and two equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. In the third Ti site, Ti(3) is bonded to one O(6), one O(9), two equivalent O(11), and two equivalent O(13) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the fourth Ti site, Ti(4) is bonded to one O(12), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and edges with two equivalent Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(7) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. In the third Si site, Si(3) is bonded to two equivalent O(8) and two equivalent O(9) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(3)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one Ti(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one Ba(2), one Ti(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Ti(4) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ba(1) and two equivalent Ti(4) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ba(2), one Ti(1), one Ti(2), and one Ti(3) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ti(4), and one Si(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(2), one Si(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to two equivalent Ba(2), one Ti(3), and one Si(3) atom. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to two equivalent Ba(1) and two equivalent Ba(2) atoms. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Ba(2) and two equivalent Ti(3) atoms. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ti(1), one Ti(2), and one Ti(4) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to two equivalent Ba(2) and two equivalent Ti(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba4Ti6Si4O25
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.932
_cell_length_b   10.089
_cell_length_c   10.089
_cell_angle_alpha   114.213
_cell_angle_beta   98.346
_cell_angle_gamma   98.346
_symmetry_Int_Tables_number   1
_cell_volume   530.669
_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
  Ba  Ba0  1  0.598  0.830  0.074  1.0
  Ba  Ba1  1  0.402  0.170  0.926  1.0
  Ba  Ba2  1  0.402  0.426  0.670  1.0
  Ba  Ba3  1  0.598  0.574  0.330  1.0
  O  O4  1  0.931  0.449  0.794  1.0
  O  O5  1  0.069  0.551  0.206  1.0
  O  O6  1  0.069  0.706  0.051  1.0
  O  O7  1  0.931  0.294  0.949  1.0
  O  O8  1  0.616  0.193  0.693  1.0
  O  O9  1  0.384  0.807  0.307  1.0
  O  O10  1  0.924  0.806  0.306  1.0
  O  O11  1  0.076  0.194  0.694  1.0
  O  O12  1  0.559  0.920  0.825  1.0
  O  O13  1  0.441  0.080  0.175  1.0
  O  O14  1  0.441  0.675  0.580  1.0
  O  O15  1  0.559  0.325  0.420  1.0
  O  O16  1  0.938  0.685  0.574  1.0
  O  O17  1  0.062  0.315  0.426  1.0
  O  O18  1  0.062  0.926  0.815  1.0
  O  O19  1  0.938  0.074  0.185  1.0
  O  O20  1  0.745  0.068  0.417  1.0
  O  O21  1  0.255  0.932  0.583  1.0
  O  O22  1  0.255  0.083  0.432  1.0
  O  O23  1  0.745  0.917  0.568  1.0
  O  O24  1  0.768  0.686  0.821  1.0
  O  O25  1  0.232  0.314  0.179  1.0
  O  O26  1  0.232  0.679  0.814  1.0
  O  O27  1  0.768  0.321  0.186  1.0
  O  O28  1  0.500  0.500  0.000  1.0
  Si  Si29  1  0.887  0.277  0.777  1.0
  Si  Si30  1  0.113  0.723  0.223  1.0
  Si  Si31  1  0.000  0.632  0.868  1.0
  Si  Si32  1  0.000  0.368  0.132  1.0
  Ti  Ti33  1  0.500  0.000  0.500  1.0
  Ti  Ti34  1  0.000  0.000  0.500  1.0
  Ti  Ti35  1  0.761  0.220  0.322  1.0
  Ti  Ti36  1  0.239  0.780  0.678  1.0
  Ti  Ti37  1  0.239  0.178  0.280  1.0
  Ti  Ti38  1  0.761  0.822  0.720  1.0
[/CIF]
.
The crystal structure described by Ba4Ti6Si4O25 crystallizes in the monoclinic P2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 11-coordinate geometry to one O(10), one O(12), one O(2), one O(3), one O(5), two equivalent O(1), two equivalent O(4), and two equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 11-coordinate geometry to one O(10), one O(11), one O(2), one O(3), one O(6), two equivalent O(13), two equivalent O(8), and two equivalent O(9) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to two equivalent O(12), two equivalent O(2), and two equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Ti(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-50°. In the second Ti site, Ti(2) is bonded to two equivalent O(12), two equivalent O(3), and two equivalent O(6) atoms to form TiO6 octahedra that share corners with two equivalent Ti(3)O6 octahedra, corners with two equivalent Ti(4)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-51°. In the third Ti site, Ti(3) is bonded to one O(6), one O(9), two equivalent O(11), and two equivalent O(13) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Si(3)O4 tetrahedra, and edges with two equivalent Ti(3)O6 octahedra. The corner-sharing octahedral tilt angles are 50°. In the fourth Ti site, Ti(4) is bonded to one O(12), one O(7), two equivalent O(4), and two equivalent O(5) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and edges with two equivalent Ti(4)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-51°. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(3), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Ti(1)O6 octahedra,  a cornercorner with one Ti(2)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra, and  a cornercorner with one Si(3)O4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. In the second Si site, Si(2) is bonded to two equivalent O(1) and two equivalent O(7) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. In the third Si site, Si(3) is bonded to two equivalent O(8) and two equivalent O(9) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(3)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 56°. There are thirteen inequivalent O sites. In the first O site, O(1) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1), one Si(1), and one Si(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(1), one Ba(2), one Ti(1), and one Si(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one Ba(2), one Ti(2), and one Si(1) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to two equivalent Ba(1) and two equivalent Ti(4) atoms. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ba(1) and two equivalent Ti(4) atoms. In the sixth O site, O(6) is bonded in a distorted trigonal planar geometry to one Ba(2), one Ti(1), one Ti(2), and one Ti(3) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to two equivalent Ba(1), one Ti(4), and one Si(2) atom. In the eighth O site, O(8) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(2), one Si(1), and one Si(3) atom. In the ninth O site, O(9) is bonded in a 4-coordinate geometry to two equivalent Ba(2), one Ti(3), and one Si(3) atom. In the tenth O site, O(10) is bonded in a rectangular see-saw-like geometry to two equivalent Ba(1) and two equivalent Ba(2) atoms. In the eleventh O site, O(11) is bonded in a distorted T-shaped geometry to one Ba(2) and two equivalent Ti(3) atoms. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ti(1), one Ti(2), and one Ti(4) atom. In the thirteenth O site, O(13) is bonded in a 4-coordinate geometry to two equivalent Ba(2) and two equivalent Ti(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Ba4Ti6Si4O25
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.932
_cell_length_b   10.089
_cell_length_c   10.089
_cell_angle_alpha   114.213
_cell_angle_beta   98.346
_cell_angle_gamma   98.346
_symmetry_Int_Tables_number   1
_cell_volume   530.669
_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
  Ba  Ba0  1  0.598  0.830  0.074  1.0
  Ba  Ba1  1  0.402  0.170  0.926  1.0
  Ba  Ba2  1  0.402  0.426  0.670  1.0
  Ba  Ba3  1  0.598  0.574  0.330  1.0
  O  O4  1  0.931  0.449  0.794  1.0
  O  O5  1  0.069  0.551  0.206  1.0
  O  O6  1  0.069  0.706  0.051  1.0
  O  O7  1  0.931  0.294  0.949  1.0
  O  O8  1  0.616  0.193  0.693  1.0
  O  O9  1  0.384  0.807  0.307  1.0
  O  O10  1  0.924  0.806  0.306  1.0
  O  O11  1  0.076  0.194  0.694  1.0
  O  O12  1  0.559  0.920  0.825  1.0
  O  O13  1  0.441  0.080  0.175  1.0
  O  O14  1  0.441  0.675  0.580  1.0
  O  O15  1  0.559  0.325  0.420  1.0
  O  O16  1  0.938  0.685  0.574  1.0
  O  O17  1  0.062  0.315  0.426  1.0
  O  O18  1  0.062  0.926  0.815  1.0
  O  O19  1  0.938  0.074  0.185  1.0
  O  O20  1  0.745  0.068  0.417  1.0
  O  O21  1  0.255  0.932  0.583  1.0
  O  O22  1  0.255  0.083  0.432  1.0
  O  O23  1  0.745  0.917  0.568  1.0
  O  O24  1  0.768  0.686  0.821  1.0
  O  O25  1  0.232  0.314  0.179  1.0
  O  O26  1  0.232  0.679  0.814  1.0
  O  O27  1  0.768  0.321  0.186  1.0
  O  O28  1  0.500  0.500  0.000  1.0
  Si  Si29  1  0.887  0.277  0.777  1.0
  Si  Si30  1  0.113  0.723  0.223  1.0
  Si  Si31  1  0.000  0.632  0.868  1.0
  Si  Si32  1  0.000  0.368  0.132  1.0
  Ti  Ti33  1  0.500  0.000  0.500  1.0
  Ti  Ti34  1  0.000  0.000  0.500  1.0
  Ti  Ti35  1  0.761  0.220  0.322  1.0
  Ti  Ti36  1  0.239  0.780  0.678  1.0
  Ti  Ti37  1  0.239  0.178  0.280  1.0
  Ti  Ti38  1  0.761  0.822  0.720  1.0
[/CIF]
.