The structure described by La2Ti3O9 crystallizes in the monoclinic C2/m space group. There are three inequivalent La sites. In the first La site, La(1) is bonded to two equivalent O(2), two equivalent O(6), four equivalent O(4), and four equivalent O(7) atoms to form LaO12 cuboctahedra that share corners with two equivalent La(1)O12 cuboctahedra, corners with two equivalent La(2)O12 cuboctahedra, corners with four equivalent La(3)O12 cuboctahedra, faces with four equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(1)O6 octahedra, faces with two equivalent Ti(2)O6 octahedra, and faces with four equivalent Ti(3)O6 octahedra. In the second La site, La(2) is bonded to one O(6), two equivalent O(4), two equivalent O(7), three equivalent O(2), and four equivalent O(5) atoms to form LaO12 cuboctahedra that share  a cornercorner with one La(1)O12 cuboctahedra, corners with two equivalent La(3)O12 cuboctahedra, corners with three equivalent La(2)O12 cuboctahedra,  a faceface with one La(3)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(3)O6 octahedra, faces with three equivalent Ti(1)O6 octahedra, and faces with three equivalent Ti(2)O6 octahedra. In the third La site, La(3) is bonded to two equivalent O(1), two equivalent O(3), four equivalent O(4), and four equivalent O(5) atoms to form LaO12 cuboctahedra that share corners with two equivalent La(3)O12 cuboctahedra, corners with four equivalent La(1)O12 cuboctahedra, corners with four equivalent La(2)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(2)O6 octahedra, faces with two equivalent Ti(3)O6 octahedra, and faces with four equivalent Ti(1)O6 octahedra. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(5) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, faces with two equivalent La(3)O12 cuboctahedra, and faces with three equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-12°. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), two equivalent O(5), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with three equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra,  a faceface with one La(3)O12 cuboctahedra, and faces with three equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-18°. In the third Ti site, Ti(3) is bonded to one O(3), one O(6), two equivalent O(4), and two equivalent O(7) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(3)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra,  a faceface with one La(3)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-18°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to two equivalent La(3) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded to one La(1), three equivalent La(2), one Ti(1), and one Ti(2) atom to form distorted OLa4Ti2 octahedra that share corners with three equivalent O(2)La4Ti2 octahedra, corners with four equivalent O(5)La3Ti2 square pyramids, corners with six equivalent O(4)La3Ti2 square pyramids, edges with two equivalent O(2)La4Ti2 octahedra, faces with two equivalent O(4)La3Ti2 square pyramids, and faces with four equivalent O(5)La3Ti2 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one La(3), one Ti(2), and one Ti(3) atom. In the fourth O site, O(4) is bonded to one La(1), one La(2), one La(3), one Ti(1), and one Ti(3) atom to form distorted OLa3Ti2 square pyramids that share corners with three equivalent O(2)La4Ti2 octahedra, corners with four equivalent O(4)La3Ti2 square pyramids, corners with five equivalent O(5)La3Ti2 square pyramids,  an edgeedge with one O(4)La3Ti2 square pyramid,  an edgeedge with one O(5)La3Ti2 square pyramid,  a faceface with one O(2)La4Ti2 octahedra,  a faceface with one O(4)La3Ti2 square pyramid, and  a faceface with one O(5)La3Ti2 square pyramid. The corner-sharing octahedral tilt angles range from 58-60°. In the fifth O site, O(5) is bonded to one La(3), two equivalent La(2), one Ti(1), and one Ti(2) atom to form distorted OLa3Ti2 square pyramids that share corners with two equivalent O(2)La4Ti2 octahedra, corners with four equivalent O(5)La3Ti2 square pyramids, corners with five equivalent O(4)La3Ti2 square pyramids,  an edgeedge with one O(4)La3Ti2 square pyramid, edges with two equivalent O(5)La3Ti2 square pyramids, faces with two equivalent O(2)La4Ti2 octahedra,  a faceface with one O(4)La3Ti2 square pyramid, and  a faceface with one O(5)La3Ti2 square pyramid. The corner-sharing octahedral tilt angles range from 59-61°. In the sixth O site, O(6) is bonded in a distorted linear geometry to two equivalent La(1), two equivalent La(2), and two equivalent Ti(3) atoms. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one La(1), one La(2), one Ti(2), and one Ti(3) atom. is represented by the CIF card [CIF]
data_La2Ti3O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.711
_cell_length_b   8.711
_cell_length_c   9.600
_cell_angle_alpha   57.023
_cell_angle_beta   57.023
_cell_angle_gamma   36.871
_symmetry_Int_Tables_number   1
_cell_volume   357.946
_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
  La  La0  1  0.000  0.000  0.000  1.0
  La  La1  1  0.667  0.667  0.999  1.0
  La  La2  1  0.500  0.500  0.500  1.0
  La  La3  1  0.333  0.333  0.001  1.0
  Ti  Ti4  1  0.918  0.918  0.745  1.0
  Ti  Ti5  1  0.748  0.748  0.265  1.0
  Ti  Ti6  1  0.591  0.591  0.739  1.0
  Ti  Ti7  1  0.409  0.409  0.261  1.0
  Ti  Ti8  1  0.252  0.252  0.735  1.0
  Ti  Ti9  1  0.082  0.082  0.255  1.0
  O  O10  1  0.000  0.000  0.500  1.0
  O  O11  1  0.832  0.832  0.999  1.0
  O  O12  1  0.654  0.654  0.501  1.0
  O  O13  1  0.731  0.253  0.764  1.0
  O  O14  1  0.906  0.429  0.238  1.0
  O  O15  1  0.500  0.500  0.000  1.0
  O  O16  1  0.593  0.091  0.225  1.0
  O  O17  1  0.909  0.407  0.775  1.0
  O  O18  1  0.747  0.269  0.236  1.0
  O  O19  1  0.571  0.094  0.762  1.0
  O  O20  1  0.429  0.906  0.238  1.0
  O  O21  1  0.253  0.731  0.764  1.0
  O  O22  1  0.091  0.593  0.225  1.0
  O  O23  1  0.346  0.346  0.499  1.0
  O  O24  1  0.168  0.168  0.001  1.0
  O  O25  1  0.407  0.909  0.775  1.0
  O  O26  1  0.269  0.747  0.236  1.0
  O  O27  1  0.094  0.571  0.762  1.0
[/CIF]
.
The structure described by La2Ti3O9 crystallizes in the monoclinic C2/m space group. There are three inequivalent La sites. In the first La site, La(1) is bonded to two equivalent O(2), two equivalent O(6), four equivalent O(4), and four equivalent O(7) atoms to form LaO12 cuboctahedra that share corners with two equivalent La(1)O12 cuboctahedra, corners with two equivalent La(2)O12 cuboctahedra, corners with four equivalent La(3)O12 cuboctahedra, faces with four equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(1)O6 octahedra, faces with two equivalent Ti(2)O6 octahedra, and faces with four equivalent Ti(3)O6 octahedra. In the second La site, La(2) is bonded to one O(6), two equivalent O(4), two equivalent O(7), three equivalent O(2), and four equivalent O(5) atoms to form LaO12 cuboctahedra that share  a cornercorner with one La(1)O12 cuboctahedra, corners with two equivalent La(3)O12 cuboctahedra, corners with three equivalent La(2)O12 cuboctahedra,  a faceface with one La(3)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(3)O6 octahedra, faces with three equivalent Ti(1)O6 octahedra, and faces with three equivalent Ti(2)O6 octahedra. In the third La site, La(3) is bonded to two equivalent O(1), two equivalent O(3), four equivalent O(4), and four equivalent O(5) atoms to form LaO12 cuboctahedra that share corners with two equivalent La(3)O12 cuboctahedra, corners with four equivalent La(1)O12 cuboctahedra, corners with four equivalent La(2)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra, faces with two equivalent Ti(2)O6 octahedra, faces with two equivalent Ti(3)O6 octahedra, and faces with four equivalent Ti(1)O6 octahedra. There are three inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), two equivalent O(4), and two equivalent O(5) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(1)O6 octahedra, corners with two equivalent Ti(3)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, faces with two equivalent La(3)O12 cuboctahedra, and faces with three equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-12°. In the second Ti site, Ti(2) is bonded to one O(2), one O(3), two equivalent O(5), and two equivalent O(7) atoms to form TiO6 octahedra that share corners with three equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(3)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra,  a faceface with one La(3)O12 cuboctahedra, and faces with three equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-18°. In the third Ti site, Ti(3) is bonded to one O(3), one O(6), two equivalent O(4), and two equivalent O(7) atoms to form TiO6 octahedra that share  a cornercorner with one Ti(3)O6 octahedra, corners with two equivalent Ti(1)O6 octahedra, corners with three equivalent Ti(2)O6 octahedra,  a faceface with one La(3)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-18°. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to two equivalent La(3) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded to one La(1), three equivalent La(2), one Ti(1), and one Ti(2) atom to form distorted OLa4Ti2 octahedra that share corners with three equivalent O(2)La4Ti2 octahedra, corners with four equivalent O(5)La3Ti2 square pyramids, corners with six equivalent O(4)La3Ti2 square pyramids, edges with two equivalent O(2)La4Ti2 octahedra, faces with two equivalent O(4)La3Ti2 square pyramids, and faces with four equivalent O(5)La3Ti2 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded in a distorted T-shaped geometry to one La(3), one Ti(2), and one Ti(3) atom. In the fourth O site, O(4) is bonded to one La(1), one La(2), one La(3), one Ti(1), and one Ti(3) atom to form distorted OLa3Ti2 square pyramids that share corners with three equivalent O(2)La4Ti2 octahedra, corners with four equivalent O(4)La3Ti2 square pyramids, corners with five equivalent O(5)La3Ti2 square pyramids,  an edgeedge with one O(4)La3Ti2 square pyramid,  an edgeedge with one O(5)La3Ti2 square pyramid,  a faceface with one O(2)La4Ti2 octahedra,  a faceface with one O(4)La3Ti2 square pyramid, and  a faceface with one O(5)La3Ti2 square pyramid. The corner-sharing octahedral tilt angles range from 58-60°. In the fifth O site, O(5) is bonded to one La(3), two equivalent La(2), one Ti(1), and one Ti(2) atom to form distorted OLa3Ti2 square pyramids that share corners with two equivalent O(2)La4Ti2 octahedra, corners with four equivalent O(5)La3Ti2 square pyramids, corners with five equivalent O(4)La3Ti2 square pyramids,  an edgeedge with one O(4)La3Ti2 square pyramid, edges with two equivalent O(5)La3Ti2 square pyramids, faces with two equivalent O(2)La4Ti2 octahedra,  a faceface with one O(4)La3Ti2 square pyramid, and  a faceface with one O(5)La3Ti2 square pyramid. The corner-sharing octahedral tilt angles range from 59-61°. In the sixth O site, O(6) is bonded in a distorted linear geometry to two equivalent La(1), two equivalent La(2), and two equivalent Ti(3) atoms. In the seventh O site, O(7) is bonded in a distorted rectangular see-saw-like geometry to one La(1), one La(2), one Ti(2), and one Ti(3) atom. is represented by the CIF card [CIF]
data_La2Ti3O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.711
_cell_length_b   8.711
_cell_length_c   9.600
_cell_angle_alpha   57.023
_cell_angle_beta   57.023
_cell_angle_gamma   36.871
_symmetry_Int_Tables_number   1
_cell_volume   357.946
_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
  La  La0  1  0.000  0.000  0.000  1.0
  La  La1  1  0.667  0.667  0.999  1.0
  La  La2  1  0.500  0.500  0.500  1.0
  La  La3  1  0.333  0.333  0.001  1.0
  Ti  Ti4  1  0.918  0.918  0.745  1.0
  Ti  Ti5  1  0.748  0.748  0.265  1.0
  Ti  Ti6  1  0.591  0.591  0.739  1.0
  Ti  Ti7  1  0.409  0.409  0.261  1.0
  Ti  Ti8  1  0.252  0.252  0.735  1.0
  Ti  Ti9  1  0.082  0.082  0.255  1.0
  O  O10  1  0.000  0.000  0.500  1.0
  O  O11  1  0.832  0.832  0.999  1.0
  O  O12  1  0.654  0.654  0.501  1.0
  O  O13  1  0.731  0.253  0.764  1.0
  O  O14  1  0.906  0.429  0.238  1.0
  O  O15  1  0.500  0.500  0.000  1.0
  O  O16  1  0.593  0.091  0.225  1.0
  O  O17  1  0.909  0.407  0.775  1.0
  O  O18  1  0.747  0.269  0.236  1.0
  O  O19  1  0.571  0.094  0.762  1.0
  O  O20  1  0.429  0.906  0.238  1.0
  O  O21  1  0.253  0.731  0.764  1.0
  O  O22  1  0.091  0.593  0.225  1.0
  O  O23  1  0.346  0.346  0.499  1.0
  O  O24  1  0.168  0.168  0.001  1.0
  O  O25  1  0.407  0.909  0.775  1.0
  O  O26  1  0.269  0.747  0.236  1.0
  O  O27  1  0.094  0.571  0.762  1.0
[/CIF]
.