The structure described by Sm3TaO7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. In the second Sm site, Sm(2) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O6 octahedra, corners with three equivalent Sm(2)O7 pentagonal bipyramids, edges with two equivalent Ta(1)O6 octahedra, and edges with two equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 34-43°. 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 Sm(2)O7 pentagonal bipyramids, and edges with four equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 34°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Sm(1), two equivalent Sm(2), and one Ta(1) atom to form distorted OSm3Ta tetrahedra that share corners with four equivalent O(4)Sm4 tetrahedra, edges with two equivalent O(1)Sm3Ta tetrahedra, and edges with two equivalent O(4)Sm4 tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Sm(2) and one Ta(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Sm(2) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with four equivalent O(1)Sm3Ta tetrahedra, corners with six equivalent O(4)Sm4 tetrahedra,  an edgeedge with one O(4)Sm4 tetrahedra, and edges with two equivalent O(1)Sm3Ta tetrahedra. is represented by the CIF card [CIF]
data_Sm3TaO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.597
_cell_length_b   7.678
_cell_length_c   10.839
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   632.247
_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
  Sm  Sm0  1  0.012  0.794  0.250  1.0
  Sm  Sm1  1  0.252  0.962  0.522  1.0
  Sm  Sm2  1  0.252  0.962  0.978  1.0
  Sm  Sm3  1  0.248  0.462  0.022  1.0
  Sm  Sm4  1  0.248  0.462  0.478  1.0
  Sm  Sm5  1  0.488  0.294  0.750  1.0
  Sm  Sm6  1  0.512  0.706  0.250  1.0
  Sm  Sm7  1  0.752  0.538  0.522  1.0
  Sm  Sm8  1  0.752  0.538  0.978  1.0
  Sm  Sm9  1  0.748  0.038  0.022  1.0
  Sm  Sm10  1  0.748  0.038  0.478  1.0
  Sm  Sm11  1  0.988  0.206  0.750  1.0
  Ta  Ta12  1  0.999  0.749  0.750  1.0
  Ta  Ta13  1  0.501  0.249  0.250  1.0
  Ta  Ta14  1  0.499  0.751  0.750  1.0
  Ta  Ta15  1  0.001  0.251  0.250  1.0
  O  O16  1  0.034  0.050  0.126  1.0
  O  O17  1  0.034  0.050  0.374  1.0
  O  O18  1  0.039  0.587  0.614  1.0
  O  O19  1  0.039  0.587  0.886  1.0
  O  O20  1  0.248  0.325  0.250  1.0
  O  O21  1  0.255  0.731  0.117  1.0
  O  O22  1  0.255  0.731  0.383  1.0
  O  O23  1  0.245  0.231  0.617  1.0
  O  O24  1  0.245  0.231  0.883  1.0
  O  O25  1  0.252  0.825  0.750  1.0
  O  O26  1  0.461  0.087  0.114  1.0
  O  O27  1  0.461  0.087  0.386  1.0
  O  O28  1  0.466  0.550  0.626  1.0
  O  O29  1  0.466  0.550  0.874  1.0
  O  O30  1  0.534  0.450  0.126  1.0
  O  O31  1  0.534  0.450  0.374  1.0
  O  O32  1  0.539  0.913  0.614  1.0
  O  O33  1  0.539  0.913  0.886  1.0
  O  O34  1  0.748  0.175  0.250  1.0
  O  O35  1  0.755  0.769  0.117  1.0
  O  O36  1  0.755  0.769  0.383  1.0
  O  O37  1  0.745  0.269  0.617  1.0
  O  O38  1  0.745  0.269  0.883  1.0
  O  O39  1  0.752  0.675  0.750  1.0
  O  O40  1  0.961  0.413  0.114  1.0
  O  O41  1  0.961  0.413  0.386  1.0
  O  O42  1  0.966  0.950  0.626  1.0
  O  O43  1  0.966  0.950  0.874  1.0
[/CIF]
.
The structure described by Sm3TaO7 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Sm sites. In the first Sm site, Sm(1) is bonded in a 6-coordinate geometry to two equivalent O(1) and four equivalent O(4) atoms. In the second Sm site, Sm(2) is bonded to one O(3), two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent Ta(1)O6 octahedra, corners with three equivalent Sm(2)O7 pentagonal bipyramids, edges with two equivalent Ta(1)O6 octahedra, and edges with two equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 34-43°. 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 Sm(2)O7 pentagonal bipyramids, and edges with four equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 34°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Sm(1), two equivalent Sm(2), and one Ta(1) atom to form distorted OSm3Ta tetrahedra that share corners with four equivalent O(4)Sm4 tetrahedra, edges with two equivalent O(1)Sm3Ta tetrahedra, and edges with two equivalent O(4)Sm4 tetrahedra. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Sm(2) and one Ta(1) atom. In the third O site, O(3) is bonded in a distorted bent 150 degrees geometry to two equivalent Sm(2) and two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded to two equivalent Sm(1) and two equivalent Sm(2) atoms to form OSm4 tetrahedra that share corners with four equivalent O(1)Sm3Ta tetrahedra, corners with six equivalent O(4)Sm4 tetrahedra,  an edgeedge with one O(4)Sm4 tetrahedra, and edges with two equivalent O(1)Sm3Ta tetrahedra. is represented by the CIF card [CIF]
data_Sm3TaO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.597
_cell_length_b   7.678
_cell_length_c   10.839
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   632.247
_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
  Sm  Sm0  1  0.012  0.794  0.250  1.0
  Sm  Sm1  1  0.252  0.962  0.522  1.0
  Sm  Sm2  1  0.252  0.962  0.978  1.0
  Sm  Sm3  1  0.248  0.462  0.022  1.0
  Sm  Sm4  1  0.248  0.462  0.478  1.0
  Sm  Sm5  1  0.488  0.294  0.750  1.0
  Sm  Sm6  1  0.512  0.706  0.250  1.0
  Sm  Sm7  1  0.752  0.538  0.522  1.0
  Sm  Sm8  1  0.752  0.538  0.978  1.0
  Sm  Sm9  1  0.748  0.038  0.022  1.0
  Sm  Sm10  1  0.748  0.038  0.478  1.0
  Sm  Sm11  1  0.988  0.206  0.750  1.0
  Ta  Ta12  1  0.999  0.749  0.750  1.0
  Ta  Ta13  1  0.501  0.249  0.250  1.0
  Ta  Ta14  1  0.499  0.751  0.750  1.0
  Ta  Ta15  1  0.001  0.251  0.250  1.0
  O  O16  1  0.034  0.050  0.126  1.0
  O  O17  1  0.034  0.050  0.374  1.0
  O  O18  1  0.039  0.587  0.614  1.0
  O  O19  1  0.039  0.587  0.886  1.0
  O  O20  1  0.248  0.325  0.250  1.0
  O  O21  1  0.255  0.731  0.117  1.0
  O  O22  1  0.255  0.731  0.383  1.0
  O  O23  1  0.245  0.231  0.617  1.0
  O  O24  1  0.245  0.231  0.883  1.0
  O  O25  1  0.252  0.825  0.750  1.0
  O  O26  1  0.461  0.087  0.114  1.0
  O  O27  1  0.461  0.087  0.386  1.0
  O  O28  1  0.466  0.550  0.626  1.0
  O  O29  1  0.466  0.550  0.874  1.0
  O  O30  1  0.534  0.450  0.126  1.0
  O  O31  1  0.534  0.450  0.374  1.0
  O  O32  1  0.539  0.913  0.614  1.0
  O  O33  1  0.539  0.913  0.886  1.0
  O  O34  1  0.748  0.175  0.250  1.0
  O  O35  1  0.755  0.769  0.117  1.0
  O  O36  1  0.755  0.769  0.383  1.0
  O  O37  1  0.745  0.269  0.617  1.0
  O  O38  1  0.745  0.269  0.883  1.0
  O  O39  1  0.752  0.675  0.750  1.0
  O  O40  1  0.961  0.413  0.114  1.0
  O  O41  1  0.961  0.413  0.386  1.0
  O  O42  1  0.966  0.950  0.626  1.0
  O  O43  1  0.966  0.950  0.874  1.0
[/CIF]
.