The material structure described by Tb3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to one O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Tb(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Ga(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form GaO4 tetrahedra that share  a cornercorner with one Tb(1)O7 pentagonal bipyramid and  an edgeedge with one Tb(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Tb(1), two equivalent Tb(2), and one Ga(1) atom to form distorted OTb3Ga tetrahedra that share corners with eight equivalent O(3)Tb4 tetrahedra,  a cornercorner with one O(2)Tb4Ga trigonal bipyramid, corners with four equivalent O(4)Tb3Ga trigonal pyramids, edges with two equivalent O(2)Tb4Ga trigonal bipyramids, and edges with two equivalent O(4)Tb3Ga trigonal pyramids. In the second O site, O(2) is bonded to four equivalent Tb(2) and one Ga(1) atom to form distorted OTb4Ga trigonal bipyramids that share  a cornercorner with one O(1)Tb3Ga tetrahedra, corners with four equivalent O(3)Tb4 tetrahedra, corners with six equivalent O(4)Tb3Ga trigonal pyramids, edges with two equivalent O(1)Tb3Ga tetrahedra, edges with two equivalent O(3)Tb4 tetrahedra, edges with two equivalent O(2)Tb4Ga trigonal bipyramids, and edges with two equivalent O(4)Tb3Ga trigonal pyramids. In the third O site, O(3) 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)Tb4 tetrahedra, corners with four equivalent O(1)Tb3Ga tetrahedra, corners with two equivalent O(2)Tb4Ga trigonal bipyramids, corners with six equivalent O(4)Tb3Ga trigonal pyramids, edges with three equivalent O(3)Tb4 tetrahedra,  an edgeedge with one O(2)Tb4Ga trigonal bipyramid, and  an edgeedge with one O(4)Tb3Ga trigonal pyramid. In the fourth O site, O(4) is bonded to one Tb(1), two equivalent Tb(2), and one Ga(1) atom to form distorted OTb3Ga trigonal pyramids that share corners with two equivalent O(1)Tb3Ga tetrahedra, corners with six equivalent O(3)Tb4 tetrahedra, corners with three equivalent O(2)Tb4Ga trigonal bipyramids, corners with two equivalent O(4)Tb3Ga trigonal pyramids,  an edgeedge with one O(1)Tb3Ga tetrahedra,  an edgeedge with one O(3)Tb4 tetrahedra,  an edgeedge with one O(2)Tb4Ga trigonal bipyramid, and  an edgeedge with one O(4)Tb3Ga trigonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_Tb3GaO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.431
_cell_length_b   7.119
_cell_length_c   7.119
_cell_angle_alpha   102.838
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   268.345
_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
  Tb  Tb0  1  0.078  0.602  0.398  1.0
  Tb  Tb1  1  0.578  0.398  0.602  1.0
  Tb  Tb2  1  0.031  0.088  0.299  1.0
  Tb  Tb3  1  0.531  0.912  0.701  1.0
  Tb  Tb4  1  0.031  0.701  0.912  1.0
  Tb  Tb5  1  0.531  0.299  0.088  1.0
  Ga  Ga6  1  0.500  0.807  0.193  1.0
  Ga  Ga7  1  1.000  0.193  0.807  1.0
  O  O8  1  0.835  0.784  0.216  1.0
  O  O9  1  0.335  0.216  0.784  1.0
  O  O10  1  0.359  0.961  0.039  1.0
  O  O11  1  0.859  0.039  0.961  1.0
  O  O12  1  0.303  0.324  0.356  1.0
  O  O13  1  0.803  0.676  0.644  1.0
  O  O14  1  0.303  0.644  0.676  1.0
  O  O15  1  0.803  0.356  0.324  1.0
  O  O16  1  0.823  0.421  0.895  1.0
  O  O17  1  0.323  0.579  0.105  1.0
  O  O18  1  0.823  0.105  0.579  1.0
  O  O19  1  0.323  0.895  0.421  1.0
[/CIF]
.
The material structure described by Tb3GaO6 crystallizes in the orthorhombic Cmc2_1 space group. There are two inequivalent Tb sites. In the first Tb site, Tb(1) is bonded to one O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted TbO7 pentagonal bipyramids that share  a cornercorner with one Ga(1)O4 tetrahedra, edges with two equivalent Tb(1)O7 pentagonal bipyramids, and  an edgeedge with one Ga(1)O4 tetrahedra. In the second Tb site, Tb(2) is bonded in a 7-coordinate geometry to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. Ga(1) is bonded to one O(1), one O(2), and two equivalent O(4) atoms to form GaO4 tetrahedra that share  a cornercorner with one Tb(1)O7 pentagonal bipyramid and  an edgeedge with one Tb(1)O7 pentagonal bipyramid. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Tb(1), two equivalent Tb(2), and one Ga(1) atom to form distorted OTb3Ga tetrahedra that share corners with eight equivalent O(3)Tb4 tetrahedra,  a cornercorner with one O(2)Tb4Ga trigonal bipyramid, corners with four equivalent O(4)Tb3Ga trigonal pyramids, edges with two equivalent O(2)Tb4Ga trigonal bipyramids, and edges with two equivalent O(4)Tb3Ga trigonal pyramids. In the second O site, O(2) is bonded to four equivalent Tb(2) and one Ga(1) atom to form distorted OTb4Ga trigonal bipyramids that share  a cornercorner with one O(1)Tb3Ga tetrahedra, corners with four equivalent O(3)Tb4 tetrahedra, corners with six equivalent O(4)Tb3Ga trigonal pyramids, edges with two equivalent O(1)Tb3Ga tetrahedra, edges with two equivalent O(3)Tb4 tetrahedra, edges with two equivalent O(2)Tb4Ga trigonal bipyramids, and edges with two equivalent O(4)Tb3Ga trigonal pyramids. In the third O site, O(3) 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)Tb4 tetrahedra, corners with four equivalent O(1)Tb3Ga tetrahedra, corners with two equivalent O(2)Tb4Ga trigonal bipyramids, corners with six equivalent O(4)Tb3Ga trigonal pyramids, edges with three equivalent O(3)Tb4 tetrahedra,  an edgeedge with one O(2)Tb4Ga trigonal bipyramid, and  an edgeedge with one O(4)Tb3Ga trigonal pyramid. In the fourth O site, O(4) is bonded to one Tb(1), two equivalent Tb(2), and one Ga(1) atom to form distorted OTb3Ga trigonal pyramids that share corners with two equivalent O(1)Tb3Ga tetrahedra, corners with six equivalent O(3)Tb4 tetrahedra, corners with three equivalent O(2)Tb4Ga trigonal bipyramids, corners with two equivalent O(4)Tb3Ga trigonal pyramids,  an edgeedge with one O(1)Tb3Ga tetrahedra,  an edgeedge with one O(3)Tb4 tetrahedra,  an edgeedge with one O(2)Tb4Ga trigonal bipyramid, and  an edgeedge with one O(4)Tb3Ga trigonal pyramid. is represented by the Crystallographic Information File (CIF) [CIF]
data_Tb3GaO6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.431
_cell_length_b   7.119
_cell_length_c   7.119
_cell_angle_alpha   102.838
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   268.345
_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
  Tb  Tb0  1  0.078  0.602  0.398  1.0
  Tb  Tb1  1  0.578  0.398  0.602  1.0
  Tb  Tb2  1  0.031  0.088  0.299  1.0
  Tb  Tb3  1  0.531  0.912  0.701  1.0
  Tb  Tb4  1  0.031  0.701  0.912  1.0
  Tb  Tb5  1  0.531  0.299  0.088  1.0
  Ga  Ga6  1  0.500  0.807  0.193  1.0
  Ga  Ga7  1  1.000  0.193  0.807  1.0
  O  O8  1  0.835  0.784  0.216  1.0
  O  O9  1  0.335  0.216  0.784  1.0
  O  O10  1  0.359  0.961  0.039  1.0
  O  O11  1  0.859  0.039  0.961  1.0
  O  O12  1  0.303  0.324  0.356  1.0
  O  O13  1  0.803  0.676  0.644  1.0
  O  O14  1  0.303  0.644  0.676  1.0
  O  O15  1  0.803  0.356  0.324  1.0
  O  O16  1  0.823  0.421  0.895  1.0
  O  O17  1  0.323  0.579  0.105  1.0
  O  O18  1  0.823  0.105  0.579  1.0
  O  O19  1  0.323  0.895  0.421  1.0
[/CIF]
.