The material structure described by LaNb3O9 crystallizes in the monoclinic Cm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded to one O(1), one O(3), two equivalent O(10), two equivalent O(2), two equivalent O(4), two equivalent O(7), and two equivalent O(8) atoms to form LaO12 cuboctahedra that share  a cornercorner with one La(2)O12 cuboctahedra, corners with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(5)O6 octahedra,  a faceface with one Nb(6)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Nb(4)O6 octahedra. In the second La site, La(2) is bonded to one O(1), one O(4), two equivalent O(10), two equivalent O(12), two equivalent O(3), two equivalent O(7), and two equivalent O(9) atoms to form LaO12 cuboctahedra that share  a cornercorner with one La(1)O12 cuboctahedra, corners with two equivalent La(2)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Nb(6)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Nb(5)O6 octahedra. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(6), two equivalent O(12), and two equivalent O(8) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(6)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and  a faceface with one La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-15°. In the second Nb site, Nb(2) is bonded to one O(4), one O(6), two equivalent O(2), and two equivalent O(7) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra,  a faceface with one La(2)O12 cuboctahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the third Nb site, Nb(3) is bonded to one O(3), one O(5), two equivalent O(7), and two equivalent O(9) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the fourth Nb site, Nb(4) is bonded to one O(4), one O(5), two equivalent O(10), and two equivalent O(8) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra,  a faceface with one La(2)O12 cuboctahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-18°. In the fifth Nb site, Nb(5) is bonded to one O(11), one O(3), two equivalent O(10), and two equivalent O(12) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(6)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-18°. In the sixth Nb site, Nb(6) is bonded to one O(1), one O(11), two equivalent O(2), and two equivalent O(9) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and  a faceface with one La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-13°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one La(1), one La(2), one Nb(1), and one Nb(6) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one La(1), one Nb(2), and one Nb(6) atom. In the third O site, O(3) is bonded to one La(1), two equivalent La(2), one Nb(3), and one Nb(5) atom to form a mixture of distorted corner and edge-sharing OLa3Nb2 square pyramids. In the fourth O site, O(4) is bonded to one La(2), two equivalent La(1), one Nb(2), and one Nb(4) atom to form a mixture of distorted corner and edge-sharing OLa3Nb2 square pyramids. In the fifth O site, O(5) is bonded in a linear geometry to one Nb(3) and one Nb(4) atom. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. 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 Nb(2), and one Nb(3) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one La(1), one Nb(1), and one Nb(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one La(2), one Nb(3), and one Nb(6) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one La(1), one La(2), one Nb(4), and one Nb(5) atom. In the eleventh O site, O(11) is bonded in a linear geometry to one Nb(5) and one Nb(6) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one La(2), one Nb(1), and one Nb(5) atom. is represented by the CIF card [CIF]
data_LaNb3O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.904
_cell_length_b   8.904
_cell_length_c   9.817
_cell_angle_alpha   57.009
_cell_angle_beta   57.009
_cell_angle_gamma   36.818
_symmetry_Int_Tables_number   1
_cell_volume   381.948
_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  0.334  0.334  0.999  1.0
  La  La1  1  0.673  0.673  0.998  1.0
  Nb  Nb2  1  0.589  0.589  0.747  1.0
  Nb  Nb3  1  0.750  0.750  0.264  1.0
  Nb  Nb4  1  0.079  0.079  0.257  1.0
  Nb  Nb5  1  0.929  0.929  0.739  1.0
  Nb  Nb6  1  0.257  0.257  0.732  1.0
  Nb  Nb7  1  0.418  0.418  0.248  1.0
  O  O8  1  0.504  0.504  1.000  1.0
  O  O9  1  0.579  0.102  0.230  1.0
  O  O10  1  0.102  0.579  0.230  1.0
  O  O11  1  0.179  0.179  0.001  1.0
  O  O12  1  0.831  0.831  0.998  1.0
  O  O13  1  0.005  0.005  0.499  1.0
  O  O14  1  0.669  0.669  0.502  1.0
  O  O15  1  0.924  0.436  0.224  1.0
  O  O16  1  0.730  0.259  0.767  1.0
  O  O17  1  0.750  0.278  0.232  1.0
  O  O18  1  0.259  0.730  0.767  1.0
  O  O19  1  0.436  0.924  0.224  1.0
  O  O20  1  0.574  0.083  0.775  1.0
  O  O21  1  0.339  0.339  0.497  1.0
  O  O22  1  0.083  0.574  0.775  1.0
  O  O23  1  0.278  0.750  0.232  1.0
  O  O24  1  0.907  0.428  0.769  1.0
  O  O25  1  0.428  0.907  0.769  1.0
[/CIF]
.
The material structure described by LaNb3O9 crystallizes in the monoclinic Cm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded to one O(1), one O(3), two equivalent O(10), two equivalent O(2), two equivalent O(4), two equivalent O(7), and two equivalent O(8) atoms to form LaO12 cuboctahedra that share  a cornercorner with one La(2)O12 cuboctahedra, corners with two equivalent La(1)O12 cuboctahedra, faces with two equivalent La(2)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(3)O6 octahedra,  a faceface with one Nb(5)O6 octahedra,  a faceface with one Nb(6)O6 octahedra, faces with two equivalent Nb(2)O6 octahedra, and faces with two equivalent Nb(4)O6 octahedra. In the second La site, La(2) is bonded to one O(1), one O(4), two equivalent O(10), two equivalent O(12), two equivalent O(3), two equivalent O(7), and two equivalent O(9) atoms to form LaO12 cuboctahedra that share  a cornercorner with one La(1)O12 cuboctahedra, corners with two equivalent La(2)O12 cuboctahedra, faces with two equivalent La(1)O12 cuboctahedra,  a faceface with one Nb(1)O6 octahedra,  a faceface with one Nb(2)O6 octahedra,  a faceface with one Nb(4)O6 octahedra,  a faceface with one Nb(6)O6 octahedra, faces with two equivalent Nb(3)O6 octahedra, and faces with two equivalent Nb(5)O6 octahedra. There are six inequivalent Nb sites. In the first Nb site, Nb(1) is bonded to one O(1), one O(6), two equivalent O(12), and two equivalent O(8) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(6)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and  a faceface with one La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-15°. In the second Nb site, Nb(2) is bonded to one O(4), one O(6), two equivalent O(2), and two equivalent O(7) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(4)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra,  a faceface with one La(2)O12 cuboctahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the third Nb site, Nb(3) is bonded to one O(3), one O(5), two equivalent O(7), and two equivalent O(9) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(4)O6 octahedra,  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(6)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-17°. In the fourth Nb site, Nb(4) is bonded to one O(4), one O(5), two equivalent O(10), and two equivalent O(8) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(2)O6 octahedra,  a cornercorner with one Nb(3)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(5)O6 octahedra,  a faceface with one La(2)O12 cuboctahedra, and faces with two equivalent La(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 2-18°. In the fifth Nb site, Nb(5) is bonded to one O(11), one O(3), two equivalent O(10), and two equivalent O(12) atoms to form distorted NbO6 octahedra that share  a cornercorner with one Nb(3)O6 octahedra,  a cornercorner with one Nb(6)O6 octahedra, corners with two equivalent Nb(1)O6 octahedra, corners with two equivalent Nb(4)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and faces with two equivalent La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 3-18°. In the sixth Nb site, Nb(6) is bonded to one O(1), one O(11), two equivalent O(2), and two equivalent O(9) atoms to form NbO6 octahedra that share  a cornercorner with one Nb(1)O6 octahedra,  a cornercorner with one Nb(5)O6 octahedra, corners with two equivalent Nb(2)O6 octahedra, corners with two equivalent Nb(3)O6 octahedra,  a faceface with one La(1)O12 cuboctahedra, and  a faceface with one La(2)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 1-13°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted linear geometry to one La(1), one La(2), one Nb(1), and one Nb(6) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one La(1), one Nb(2), and one Nb(6) atom. In the third O site, O(3) is bonded to one La(1), two equivalent La(2), one Nb(3), and one Nb(5) atom to form a mixture of distorted corner and edge-sharing OLa3Nb2 square pyramids. In the fourth O site, O(4) is bonded to one La(2), two equivalent La(1), one Nb(2), and one Nb(4) atom to form a mixture of distorted corner and edge-sharing OLa3Nb2 square pyramids. In the fifth O site, O(5) is bonded in a linear geometry to one Nb(3) and one Nb(4) atom. In the sixth O site, O(6) is bonded in a linear geometry to one Nb(1) and one Nb(2) atom. 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 Nb(2), and one Nb(3) atom. In the eighth O site, O(8) is bonded in a distorted T-shaped geometry to one La(1), one Nb(1), and one Nb(4) atom. In the ninth O site, O(9) is bonded in a distorted T-shaped geometry to one La(2), one Nb(3), and one Nb(6) atom. In the tenth O site, O(10) is bonded in a distorted rectangular see-saw-like geometry to one La(1), one La(2), one Nb(4), and one Nb(5) atom. In the eleventh O site, O(11) is bonded in a linear geometry to one Nb(5) and one Nb(6) atom. In the twelfth O site, O(12) is bonded in a distorted T-shaped geometry to one La(2), one Nb(1), and one Nb(5) atom. is represented by the CIF card [CIF]
data_LaNb3O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   8.904
_cell_length_b   8.904
_cell_length_c   9.817
_cell_angle_alpha   57.009
_cell_angle_beta   57.009
_cell_angle_gamma   36.818
_symmetry_Int_Tables_number   1
_cell_volume   381.948
_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  0.334  0.334  0.999  1.0
  La  La1  1  0.673  0.673  0.998  1.0
  Nb  Nb2  1  0.589  0.589  0.747  1.0
  Nb  Nb3  1  0.750  0.750  0.264  1.0
  Nb  Nb4  1  0.079  0.079  0.257  1.0
  Nb  Nb5  1  0.929  0.929  0.739  1.0
  Nb  Nb6  1  0.257  0.257  0.732  1.0
  Nb  Nb7  1  0.418  0.418  0.248  1.0
  O  O8  1  0.504  0.504  1.000  1.0
  O  O9  1  0.579  0.102  0.230  1.0
  O  O10  1  0.102  0.579  0.230  1.0
  O  O11  1  0.179  0.179  0.001  1.0
  O  O12  1  0.831  0.831  0.998  1.0
  O  O13  1  0.005  0.005  0.499  1.0
  O  O14  1  0.669  0.669  0.502  1.0
  O  O15  1  0.924  0.436  0.224  1.0
  O  O16  1  0.730  0.259  0.767  1.0
  O  O17  1  0.750  0.278  0.232  1.0
  O  O18  1  0.259  0.730  0.767  1.0
  O  O19  1  0.436  0.924  0.224  1.0
  O  O20  1  0.574  0.083  0.775  1.0
  O  O21  1  0.339  0.339  0.497  1.0
  O  O22  1  0.083  0.574  0.775  1.0
  O  O23  1  0.278  0.750  0.232  1.0
  O  O24  1  0.907  0.428  0.769  1.0
  O  O25  1  0.428  0.907  0.769  1.0
[/CIF]
.