The crystal structure described by La4Ti9(Si2O15)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one O(2), one O(8), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to one O(2), one O(4), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(11), one O(4), one O(5), one O(7), one O(8), and one O(9) atom to form TiO6 octahedra that share corners with three equivalent Ti(2)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-50°. In the second Ti site, Ti(2) is bonded to one O(5), one O(8), two equivalent O(6), and two equivalent O(9) atoms to form a mixture of distorted edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 48-50°. In the third Ti site, Ti(3) is bonded to one O(11), one O(4), two equivalent O(6), and two equivalent O(9) atoms to form a mixture of distorted edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 46-49°. In the fourth Ti site, Ti(4) is bonded to two equivalent O(10) and four equivalent O(3) atoms to form TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with four equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(10), and two equivalent O(7) atoms to form SiO4 tetrahedra that share  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 29-54°. In the second Si site, Si(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one La(1), one La(2), and one Si(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Ti(4), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one La(2), one Ti(3), and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(2) and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one La(1), one La(2), one Ti(2), and one Ti(3) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Ti(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one La(1), one Ti(2), and two equivalent Ti(1) atoms. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ti(1), one Ti(2), and one Ti(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Ti(4) and one Si(1) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_La4Ti9(Si2O15)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.440
_cell_length_b   7.440
_cell_length_c   14.349
_cell_angle_alpha   84.961
_cell_angle_beta   84.961
_cell_angle_gamma   45.758
_symmetry_Int_Tables_number   1
_cell_volume   566.424
_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
  La  La0  1  0.983  0.983  0.309  1.0
  La  La1  1  0.701  0.701  0.314  1.0
  La  La2  1  0.299  0.299  0.686  1.0
  La  La3  1  0.017  0.017  0.691  1.0
  Ti  Ti4  1  0.900  0.372  0.890  1.0
  Ti  Ti5  1  0.131  0.131  0.118  1.0
  Ti  Ti6  1  0.596  0.596  0.118  1.0
  Ti  Ti7  1  0.372  0.900  0.890  1.0
  Ti  Ti8  1  0.404  0.404  0.882  1.0
  Ti  Ti9  1  0.628  0.100  0.110  1.0
  Ti  Ti10  1  0.869  0.869  0.882  1.0
  Ti  Ti11  1  0.500  0.500  0.500  1.0
  Ti  Ti12  1  0.100  0.628  0.110  1.0
  Si  Si13  1  0.347  0.347  0.322  1.0
  Si  Si14  1  0.653  0.653  0.678  1.0
  Si  Si15  1  0.853  0.853  0.534  1.0
  Si  Si16  1  0.147  0.147  0.466  1.0
  O  O17  1  0.753  0.753  0.608  1.0
  O  O18  1  0.166  0.166  0.574  1.0
  O  O19  1  0.145  0.678  0.567  1.0
  O  O20  1  0.761  0.761  0.133  1.0
  O  O21  1  0.247  0.247  0.392  1.0
  O  O22  1  0.855  0.322  0.433  1.0
  O  O23  1  0.734  0.734  0.883  1.0
  O  O24  1  0.646  0.145  0.784  1.0
  O  O25  1  0.414  0.891  0.739  1.0
  O  O26  1  0.322  0.855  0.433  1.0
  O  O27  1  0.109  0.586  0.261  1.0
  O  O28  1  0.239  0.239  0.867  1.0
  O  O29  1  0.962  0.962  0.135  1.0
  O  O30  1  0.874  0.370  0.025  1.0
  O  O31  1  0.834  0.834  0.426  1.0
  O  O32  1  0.558  0.558  0.618  1.0
  O  O33  1  0.370  0.874  0.025  1.0
  O  O34  1  0.855  0.354  0.216  1.0
  O  O35  1  0.586  0.109  0.261  1.0
  O  O36  1  0.678  0.145  0.567  1.0
  O  O37  1  0.630  0.126  0.975  1.0
  O  O38  1  0.145  0.646  0.784  1.0
  O  O39  1  0.354  0.855  0.216  1.0
  O  O40  1  0.461  0.461  0.119  1.0
  O  O41  1  0.266  0.266  0.117  1.0
  O  O42  1  0.038  0.038  0.865  1.0
  O  O43  1  0.442  0.442  0.382  1.0
  O  O44  1  0.539  0.539  0.881  1.0
  O  O45  1  0.891  0.414  0.739  1.0
  O  O46  1  0.126  0.630  0.975  1.0
[/CIF]
.
The crystal structure described by La4Ti9(Si2O15)2 crystallizes in the monoclinic C2/m space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to one O(2), one O(8), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to one O(2), one O(4), two equivalent O(3), two equivalent O(6), and two equivalent O(7) atoms. There are four inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(11), one O(4), one O(5), one O(7), one O(8), and one O(9) atom to form TiO6 octahedra that share corners with three equivalent Ti(2)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-50°. In the second Ti site, Ti(2) is bonded to one O(5), one O(8), two equivalent O(6), and two equivalent O(9) atoms to form a mixture of distorted edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 48-50°. In the third Ti site, Ti(3) is bonded to one O(11), one O(4), two equivalent O(6), and two equivalent O(9) atoms to form a mixture of distorted edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 46-49°. In the fourth Ti site, Ti(4) is bonded to two equivalent O(10) and four equivalent O(3) atoms to form TiO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra and corners with four equivalent Si(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(10), and two equivalent O(7) atoms to form SiO4 tetrahedra that share  a cornercorner with one Ti(4)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, and  a cornercorner with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 29-54°. In the second Si site, Si(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form SiO4 tetrahedra that share corners with two equivalent Ti(4)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to one La(1), one La(2), and one Si(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Ti(4), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one La(2), one Ti(3), and two equivalent Ti(1) atoms. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Ti(2) and two equivalent Ti(1) atoms. In the sixth O site, O(6) is bonded in a distorted see-saw-like geometry to one La(1), one La(2), one Ti(2), and one Ti(3) atom. In the seventh O site, O(7) is bonded in a 4-coordinate geometry to one La(1), one La(2), one Ti(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a 4-coordinate geometry to one La(1), one Ti(2), and two equivalent Ti(1) atoms. In the ninth O site, O(9) is bonded in a distorted trigonal planar geometry to one Ti(1), one Ti(2), and one Ti(3) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Ti(4) and one Si(1) atom. In the eleventh O site, O(11) is bonded in a distorted trigonal planar geometry to one Ti(3) and two equivalent Ti(1) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_La4Ti9(Si2O15)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.440
_cell_length_b   7.440
_cell_length_c   14.349
_cell_angle_alpha   84.961
_cell_angle_beta   84.961
_cell_angle_gamma   45.758
_symmetry_Int_Tables_number   1
_cell_volume   566.424
_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
  La  La0  1  0.983  0.983  0.309  1.0
  La  La1  1  0.701  0.701  0.314  1.0
  La  La2  1  0.299  0.299  0.686  1.0
  La  La3  1  0.017  0.017  0.691  1.0
  Ti  Ti4  1  0.900  0.372  0.890  1.0
  Ti  Ti5  1  0.131  0.131  0.118  1.0
  Ti  Ti6  1  0.596  0.596  0.118  1.0
  Ti  Ti7  1  0.372  0.900  0.890  1.0
  Ti  Ti8  1  0.404  0.404  0.882  1.0
  Ti  Ti9  1  0.628  0.100  0.110  1.0
  Ti  Ti10  1  0.869  0.869  0.882  1.0
  Ti  Ti11  1  0.500  0.500  0.500  1.0
  Ti  Ti12  1  0.100  0.628  0.110  1.0
  Si  Si13  1  0.347  0.347  0.322  1.0
  Si  Si14  1  0.653  0.653  0.678  1.0
  Si  Si15  1  0.853  0.853  0.534  1.0
  Si  Si16  1  0.147  0.147  0.466  1.0
  O  O17  1  0.753  0.753  0.608  1.0
  O  O18  1  0.166  0.166  0.574  1.0
  O  O19  1  0.145  0.678  0.567  1.0
  O  O20  1  0.761  0.761  0.133  1.0
  O  O21  1  0.247  0.247  0.392  1.0
  O  O22  1  0.855  0.322  0.433  1.0
  O  O23  1  0.734  0.734  0.883  1.0
  O  O24  1  0.646  0.145  0.784  1.0
  O  O25  1  0.414  0.891  0.739  1.0
  O  O26  1  0.322  0.855  0.433  1.0
  O  O27  1  0.109  0.586  0.261  1.0
  O  O28  1  0.239  0.239  0.867  1.0
  O  O29  1  0.962  0.962  0.135  1.0
  O  O30  1  0.874  0.370  0.025  1.0
  O  O31  1  0.834  0.834  0.426  1.0
  O  O32  1  0.558  0.558  0.618  1.0
  O  O33  1  0.370  0.874  0.025  1.0
  O  O34  1  0.855  0.354  0.216  1.0
  O  O35  1  0.586  0.109  0.261  1.0
  O  O36  1  0.678  0.145  0.567  1.0
  O  O37  1  0.630  0.126  0.975  1.0
  O  O38  1  0.145  0.646  0.784  1.0
  O  O39  1  0.354  0.855  0.216  1.0
  O  O40  1  0.461  0.461  0.119  1.0
  O  O41  1  0.266  0.266  0.117  1.0
  O  O42  1  0.038  0.038  0.865  1.0
  O  O43  1  0.442  0.442  0.382  1.0
  O  O44  1  0.539  0.539  0.881  1.0
  O  O45  1  0.891  0.414  0.739  1.0
  O  O46  1  0.126  0.630  0.975  1.0
[/CIF]
.