The structure described by Tb2TiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one O(3), two equivalent O(1), and three equivalent O(4) atoms. In the second Tb site, Tb(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form TbO6 octahedra that share corners with two equivalent Tb(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, and edges with two equivalent Tb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-65°. Ti(1) is bonded to one O(3), one O(4), one O(5), and three equivalent O(2) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Tb(2)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-64°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Tb(1) and two equivalent Tb(2) atoms to form OTb4 tetrahedra that share corners with two equivalent O(3)Tb3Ti tetrahedra, corners with four equivalent O(4)Tb3Ti tetrahedra, corners with four equivalent O(1)Tb4 tetrahedra,  an edgeedge with one O(4)Tb3Ti tetrahedra, and edges with two equivalent O(3)Tb3Ti tetrahedra. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ti(1) atoms. In the third O site, O(3) is bonded to one Tb(1), two equivalent Tb(2), and one Ti(1) atom to form OTb3Ti tetrahedra that share corners with two equivalent O(3)Tb3Ti tetrahedra, corners with two equivalent O(1)Tb4 tetrahedra, corners with four equivalent O(4)Tb3Ti tetrahedra, and edges with two equivalent O(1)Tb4 tetrahedra. In the fourth O site, O(4) is bonded to three equivalent Tb(1) and one Ti(1) atom to form OTb3Ti tetrahedra that share corners with two equivalent O(4)Tb3Ti tetrahedra, corners with four equivalent O(3)Tb3Ti tetrahedra, corners with four equivalent O(1)Tb4 tetrahedra,  an edgeedge with one O(1)Tb4 tetrahedra, and edges with two equivalent O(4)Tb3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Tb(2) and one Ti(1) atom. is represented by the CIF file [CIF]
data_Tb2TiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.648
_cell_length_b   7.488
_cell_length_c   15.651
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   427.508
_cell_formula_units_Z   4
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
  Tb  Tb0  1  0.250  0.113  0.083  1.0
  Tb  Tb1  1  0.250  0.143  0.738  1.0
  Tb  Tb2  1  0.750  0.357  0.238  1.0
  Tb  Tb3  1  0.750  0.387  0.583  1.0
  Tb  Tb4  1  0.250  0.613  0.417  1.0
  Tb  Tb5  1  0.250  0.643  0.762  1.0
  Tb  Tb6  1  0.750  0.857  0.262  1.0
  Tb  Tb7  1  0.750  0.887  0.917  1.0
  Ti  Ti8  1  0.250  0.124  0.423  1.0
  Ti  Ti9  1  0.750  0.376  0.923  1.0
  Ti  Ti10  1  0.250  0.624  0.077  1.0
  Ti  Ti11  1  0.750  0.876  0.577  1.0
  O  O12  1  0.750  0.089  0.174  1.0
  O  O13  1  0.750  0.083  0.454  1.0
  O  O14  1  0.750  0.104  0.649  1.0
  O  O15  1  0.750  0.154  0.995  1.0
  O  O16  1  0.250  0.265  0.326  1.0
  O  O17  1  0.750  0.235  0.826  1.0
  O  O18  1  0.250  0.346  0.495  1.0
  O  O19  1  0.250  0.396  0.149  1.0
  O  O20  1  0.250  0.417  0.954  1.0
  O  O21  1  0.250  0.411  0.674  1.0
  O  O22  1  0.750  0.589  0.326  1.0
  O  O23  1  0.750  0.583  0.046  1.0
  O  O24  1  0.750  0.604  0.851  1.0
  O  O25  1  0.750  0.654  0.505  1.0
  O  O26  1  0.250  0.765  0.174  1.0
  O  O27  1  0.750  0.735  0.674  1.0
  O  O28  1  0.250  0.846  0.005  1.0
  O  O29  1  0.250  0.896  0.351  1.0
  O  O30  1  0.250  0.917  0.546  1.0
  O  O31  1  0.250  0.911  0.826  1.0
[/CIF]
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The structure described by Tb2TiO5 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded in a 6-coordinate geometry to one O(3), two equivalent O(1), and three equivalent O(4) atoms. In the second Tb site, Tb(2) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(5) atoms to form TbO6 octahedra that share corners with two equivalent Tb(2)O6 octahedra, corners with four equivalent Ti(1)O6 octahedra, and edges with two equivalent Tb(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 51-65°. Ti(1) is bonded to one O(3), one O(4), one O(5), and three equivalent O(2) atoms to form distorted TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Tb(2)O6 octahedra, and edges with two equivalent Ti(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 35-64°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Tb(1) and two equivalent Tb(2) atoms to form OTb4 tetrahedra that share corners with two equivalent O(3)Tb3Ti tetrahedra, corners with four equivalent O(4)Tb3Ti tetrahedra, corners with four equivalent O(1)Tb4 tetrahedra,  an edgeedge with one O(4)Tb3Ti tetrahedra, and edges with two equivalent O(3)Tb3Ti tetrahedra. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ti(1) atoms. In the third O site, O(3) is bonded to one Tb(1), two equivalent Tb(2), and one Ti(1) atom to form OTb3Ti tetrahedra that share corners with two equivalent O(3)Tb3Ti tetrahedra, corners with two equivalent O(1)Tb4 tetrahedra, corners with four equivalent O(4)Tb3Ti tetrahedra, and edges with two equivalent O(1)Tb4 tetrahedra. In the fourth O site, O(4) is bonded to three equivalent Tb(1) and one Ti(1) atom to form OTb3Ti tetrahedra that share corners with two equivalent O(4)Tb3Ti tetrahedra, corners with four equivalent O(3)Tb3Ti tetrahedra, corners with four equivalent O(1)Tb4 tetrahedra,  an edgeedge with one O(1)Tb4 tetrahedra, and edges with two equivalent O(4)Tb3Ti tetrahedra. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to two equivalent Tb(2) and one Ti(1) atom. is represented by the CIF file [CIF]
data_Tb2TiO5
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.648
_cell_length_b   7.488
_cell_length_c   15.651
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   427.508
_cell_formula_units_Z   4
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
  Tb  Tb0  1  0.250  0.113  0.083  1.0
  Tb  Tb1  1  0.250  0.143  0.738  1.0
  Tb  Tb2  1  0.750  0.357  0.238  1.0
  Tb  Tb3  1  0.750  0.387  0.583  1.0
  Tb  Tb4  1  0.250  0.613  0.417  1.0
  Tb  Tb5  1  0.250  0.643  0.762  1.0
  Tb  Tb6  1  0.750  0.857  0.262  1.0
  Tb  Tb7  1  0.750  0.887  0.917  1.0
  Ti  Ti8  1  0.250  0.124  0.423  1.0
  Ti  Ti9  1  0.750  0.376  0.923  1.0
  Ti  Ti10  1  0.250  0.624  0.077  1.0
  Ti  Ti11  1  0.750  0.876  0.577  1.0
  O  O12  1  0.750  0.089  0.174  1.0
  O  O13  1  0.750  0.083  0.454  1.0
  O  O14  1  0.750  0.104  0.649  1.0
  O  O15  1  0.750  0.154  0.995  1.0
  O  O16  1  0.250  0.265  0.326  1.0
  O  O17  1  0.750  0.235  0.826  1.0
  O  O18  1  0.250  0.346  0.495  1.0
  O  O19  1  0.250  0.396  0.149  1.0
  O  O20  1  0.250  0.417  0.954  1.0
  O  O21  1  0.250  0.411  0.674  1.0
  O  O22  1  0.750  0.589  0.326  1.0
  O  O23  1  0.750  0.583  0.046  1.0
  O  O24  1  0.750  0.604  0.851  1.0
  O  O25  1  0.750  0.654  0.505  1.0
  O  O26  1  0.250  0.765  0.174  1.0
  O  O27  1  0.750  0.735  0.674  1.0
  O  O28  1  0.250  0.846  0.005  1.0
  O  O29  1  0.250  0.896  0.351  1.0
  O  O30  1  0.250  0.917  0.546  1.0
  O  O31  1  0.250  0.911  0.826  1.0
[/CIF]
.