The structure described by BaTi4O9 crystallizes in the orthorhombic Pmmn space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 25-34°. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), and three equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ti(1), and one Ti(2) atom. In the fourth O site, O(4) is bonded to one Ti(1) and three equivalent Ti(2) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ti(2) and two equivalent Ti(1) atoms. is represented by the CIF file [CIF]
data_BaTi4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.797
_cell_length_b   6.331
_cell_length_c   14.599
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   350.988
_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
  Ba  Ba0  1  0.000  0.712  0.500  1.0
  Ba  Ba1  1  0.500  0.288  0.000  1.0
  Ti  Ti2  1  0.500  0.254  0.378  1.0
  Ti  Ti3  1  0.000  0.746  0.122  1.0
  Ti  Ti4  1  0.500  0.254  0.622  1.0
  Ti  Ti5  1  0.000  0.746  0.878  1.0
  Ti  Ti6  1  0.500  0.807  0.288  1.0
  Ti  Ti7  1  0.000  0.193  0.212  1.0
  Ti  Ti8  1  0.500  0.807  0.712  1.0
  Ti  Ti9  1  0.000  0.193  0.788  1.0
  O  O10  1  0.500  0.339  0.500  1.0
  O  O11  1  0.000  0.661  0.000  1.0
  O  O12  1  0.500  0.562  0.346  1.0
  O  O13  1  0.000  0.438  0.154  1.0
  O  O14  1  0.500  0.562  0.654  1.0
  O  O15  1  0.000  0.438  0.846  1.0
  O  O16  1  0.500  0.957  0.401  1.0
  O  O17  1  0.000  0.043  0.099  1.0
  O  O18  1  0.500  0.957  0.599  1.0
  O  O19  1  0.000  0.043  0.901  1.0
  O  O20  1  0.000  0.849  0.260  1.0
  O  O21  1  0.500  0.151  0.240  1.0
  O  O22  1  0.000  0.849  0.740  1.0
  O  O23  1  0.500  0.151  0.760  1.0
  O  O24  1  0.000  0.259  0.349  1.0
  O  O25  1  0.500  0.741  0.151  1.0
  O  O26  1  0.000  0.259  0.651  1.0
  O  O27  1  0.500  0.741  0.849  1.0
[/CIF]
.
The structure described by BaTi4O9 crystallizes in the orthorhombic Pmmn space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(1), one O(2), one O(3), one O(4), and two equivalent O(5) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles range from 25-34°. In the second Ti site, Ti(2) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), and three equivalent O(4) atoms. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ba(1) and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to two equivalent Ba(1), one Ti(1), and one Ti(2) atom. In the third O site, O(3) is bonded in a distorted water-like geometry to two equivalent Ba(1), one Ti(1), and one Ti(2) atom. In the fourth O site, O(4) is bonded to one Ti(1) and three equivalent Ti(2) atoms to form a mixture of distorted corner and edge-sharing OTi4 trigonal pyramids. In the fifth O site, O(5) is bonded in a distorted T-shaped geometry to one Ti(2) and two equivalent Ti(1) atoms. is represented by the CIF file [CIF]
data_BaTi4O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.797
_cell_length_b   6.331
_cell_length_c   14.599
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   350.988
_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
  Ba  Ba0  1  0.000  0.712  0.500  1.0
  Ba  Ba1  1  0.500  0.288  0.000  1.0
  Ti  Ti2  1  0.500  0.254  0.378  1.0
  Ti  Ti3  1  0.000  0.746  0.122  1.0
  Ti  Ti4  1  0.500  0.254  0.622  1.0
  Ti  Ti5  1  0.000  0.746  0.878  1.0
  Ti  Ti6  1  0.500  0.807  0.288  1.0
  Ti  Ti7  1  0.000  0.193  0.212  1.0
  Ti  Ti8  1  0.500  0.807  0.712  1.0
  Ti  Ti9  1  0.000  0.193  0.788  1.0
  O  O10  1  0.500  0.339  0.500  1.0
  O  O11  1  0.000  0.661  0.000  1.0
  O  O12  1  0.500  0.562  0.346  1.0
  O  O13  1  0.000  0.438  0.154  1.0
  O  O14  1  0.500  0.562  0.654  1.0
  O  O15  1  0.000  0.438  0.846  1.0
  O  O16  1  0.500  0.957  0.401  1.0
  O  O17  1  0.000  0.043  0.099  1.0
  O  O18  1  0.500  0.957  0.599  1.0
  O  O19  1  0.000  0.043  0.901  1.0
  O  O20  1  0.000  0.849  0.260  1.0
  O  O21  1  0.500  0.151  0.240  1.0
  O  O22  1  0.000  0.849  0.740  1.0
  O  O23  1  0.500  0.151  0.760  1.0
  O  O24  1  0.000  0.259  0.349  1.0
  O  O25  1  0.500  0.741  0.151  1.0
  O  O26  1  0.000  0.259  0.651  1.0
  O  O27  1  0.500  0.741  0.849  1.0
[/CIF]
.