The compound described by Tm3TaO7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. In the second Tm site, Tm(2) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted TmO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O6 octahedra, corners with three equivalent Tm(2)O7 pentagonal bipyramids, edges with two equivalent Ta(1)O6 octahedra, and edges with two equivalent Tm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 35-45°. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with four equivalent Tm(2)O7 pentagonal bipyramids, and edges with four equivalent Tm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 40°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Tm(1), two equivalent Tm(2), and one Ta(1) atom to form distorted OTm3Ta tetrahedra that share corners with four equivalent O(4)Tm4 tetrahedra, edges with two equivalent O(1)Tm3Ta tetrahedra, and edges with two equivalent O(4)Tm4 tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Tm(2) and one Ta(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Tm(2) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Tm(1) and two equivalent Tm(2) atoms to form OTm4 tetrahedra that share corners with four equivalent O(1)Tm3Ta tetrahedra, corners with six equivalent O(4)Tm4 tetrahedra,  an edgeedge with one O(4)Tm4 tetrahedra, and edges with two equivalent O(1)Tm3Ta tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Tm3TaO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.381
_cell_length_b   7.487
_cell_length_c   10.458
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   577.891
_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
  Tm  Tm0  1  0.015  0.797  0.250  1.0
  Tm  Tm1  1  0.252  0.970  0.520  1.0
  Tm  Tm2  1  0.252  0.970  0.980  1.0
  Tm  Tm3  1  0.248  0.470  0.020  1.0
  Tm  Tm4  1  0.248  0.470  0.480  1.0
  Tm  Tm5  1  0.485  0.297  0.750  1.0
  Tm  Tm6  1  0.515  0.703  0.250  1.0
  Tm  Tm7  1  0.752  0.530  0.520  1.0
  Tm  Tm8  1  0.752  0.530  0.980  1.0
  Tm  Tm9  1  0.748  0.030  0.020  1.0
  Tm  Tm10  1  0.748  0.030  0.480  1.0
  Tm  Tm11  1  0.985  0.203  0.750  1.0
  Ta  Ta12  1  0.998  0.749  0.750  1.0
  Ta  Ta13  1  0.502  0.249  0.250  1.0
  Ta  Ta14  1  0.498  0.751  0.750  1.0
  Ta  Ta15  1  0.002  0.251  0.250  1.0
  O  O16  1  0.038  0.045  0.124  1.0
  O  O17  1  0.038  0.045  0.376  1.0
  O  O18  1  0.040  0.583  0.611  1.0
  O  O19  1  0.040  0.583  0.889  1.0
  O  O20  1  0.249  0.340  0.250  1.0
  O  O21  1  0.256  0.733  0.116  1.0
  O  O22  1  0.256  0.733  0.384  1.0
  O  O23  1  0.244  0.233  0.616  1.0
  O  O24  1  0.244  0.233  0.884  1.0
  O  O25  1  0.251  0.840  0.750  1.0
  O  O26  1  0.460  0.083  0.111  1.0
  O  O27  1  0.460  0.083  0.389  1.0
  O  O28  1  0.462  0.545  0.624  1.0
  O  O29  1  0.462  0.545  0.876  1.0
  O  O30  1  0.538  0.455  0.124  1.0
  O  O31  1  0.538  0.455  0.376  1.0
  O  O32  1  0.540  0.917  0.611  1.0
  O  O33  1  0.540  0.917  0.889  1.0
  O  O34  1  0.749  0.160  0.250  1.0
  O  O35  1  0.756  0.767  0.116  1.0
  O  O36  1  0.756  0.767  0.384  1.0
  O  O37  1  0.744  0.267  0.616  1.0
  O  O38  1  0.744  0.267  0.884  1.0
  O  O39  1  0.751  0.660  0.750  1.0
  O  O40  1  0.960  0.417  0.111  1.0
  O  O41  1  0.960  0.417  0.389  1.0
  O  O42  1  0.962  0.955  0.624  1.0
  O  O43  1  0.962  0.955  0.876  1.0
[/CIF]
.
The compound described by Tm3TaO7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Tm sites. In the first Tm site, Tm(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. In the second Tm site, Tm(2) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted TmO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O6 octahedra, corners with three equivalent Tm(2)O7 pentagonal bipyramids, edges with two equivalent Ta(1)O6 octahedra, and edges with two equivalent Tm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 35-45°. Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form TaO6 octahedra that share corners with two equivalent Ta(1)O6 octahedra, corners with four equivalent Tm(2)O7 pentagonal bipyramids, and edges with four equivalent Tm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 40°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Tm(1), two equivalent Tm(2), and one Ta(1) atom to form distorted OTm3Ta tetrahedra that share corners with four equivalent O(4)Tm4 tetrahedra, edges with two equivalent O(1)Tm3Ta tetrahedra, and edges with two equivalent O(4)Tm4 tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Tm(2) and one Ta(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Tm(2) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Tm(1) and two equivalent Tm(2) atoms to form OTm4 tetrahedra that share corners with four equivalent O(1)Tm3Ta tetrahedra, corners with six equivalent O(4)Tm4 tetrahedra,  an edgeedge with one O(4)Tm4 tetrahedra, and edges with two equivalent O(1)Tm3Ta tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Tm3TaO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.381
_cell_length_b   7.487
_cell_length_c   10.458
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   577.891
_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
  Tm  Tm0  1  0.015  0.797  0.250  1.0
  Tm  Tm1  1  0.252  0.970  0.520  1.0
  Tm  Tm2  1  0.252  0.970  0.980  1.0
  Tm  Tm3  1  0.248  0.470  0.020  1.0
  Tm  Tm4  1  0.248  0.470  0.480  1.0
  Tm  Tm5  1  0.485  0.297  0.750  1.0
  Tm  Tm6  1  0.515  0.703  0.250  1.0
  Tm  Tm7  1  0.752  0.530  0.520  1.0
  Tm  Tm8  1  0.752  0.530  0.980  1.0
  Tm  Tm9  1  0.748  0.030  0.020  1.0
  Tm  Tm10  1  0.748  0.030  0.480  1.0
  Tm  Tm11  1  0.985  0.203  0.750  1.0
  Ta  Ta12  1  0.998  0.749  0.750  1.0
  Ta  Ta13  1  0.502  0.249  0.250  1.0
  Ta  Ta14  1  0.498  0.751  0.750  1.0
  Ta  Ta15  1  0.002  0.251  0.250  1.0
  O  O16  1  0.038  0.045  0.124  1.0
  O  O17  1  0.038  0.045  0.376  1.0
  O  O18  1  0.040  0.583  0.611  1.0
  O  O19  1  0.040  0.583  0.889  1.0
  O  O20  1  0.249  0.340  0.250  1.0
  O  O21  1  0.256  0.733  0.116  1.0
  O  O22  1  0.256  0.733  0.384  1.0
  O  O23  1  0.244  0.233  0.616  1.0
  O  O24  1  0.244  0.233  0.884  1.0
  O  O25  1  0.251  0.840  0.750  1.0
  O  O26  1  0.460  0.083  0.111  1.0
  O  O27  1  0.460  0.083  0.389  1.0
  O  O28  1  0.462  0.545  0.624  1.0
  O  O29  1  0.462  0.545  0.876  1.0
  O  O30  1  0.538  0.455  0.124  1.0
  O  O31  1  0.538  0.455  0.376  1.0
  O  O32  1  0.540  0.917  0.611  1.0
  O  O33  1  0.540  0.917  0.889  1.0
  O  O34  1  0.749  0.160  0.250  1.0
  O  O35  1  0.756  0.767  0.116  1.0
  O  O36  1  0.756  0.767  0.384  1.0
  O  O37  1  0.744  0.267  0.616  1.0
  O  O38  1  0.744  0.267  0.884  1.0
  O  O39  1  0.751  0.660  0.750  1.0
  O  O40  1  0.960  0.417  0.111  1.0
  O  O41  1  0.960  0.417  0.389  1.0
  O  O42  1  0.962  0.955  0.624  1.0
  O  O43  1  0.962  0.955  0.876  1.0
[/CIF]
.