The crystal structure described by Sm3NbO7 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 Nb(1)O6 octahedra, corners with three equivalent Sm(2)O7 pentagonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with two equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 32-44°. Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(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 37°. 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 Nb(1) atom to form distorted OSm3Nb tetrahedra that share corners with four equivalent O(4)Sm4 tetrahedra, edges with two equivalent O(1)Sm3Nb 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 Nb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Sm(2) and two equivalent Nb(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)Sm3Nb tetrahedra, corners with six equivalent O(4)Sm4 tetrahedra,  an edgeedge with one O(4)Sm4 tetrahedra, and edges with two equivalent O(1)Sm3Nb tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sm3NbO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.604
_cell_length_b   7.723
_cell_length_c   10.832
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   636.103
_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  0.015  0.798  0.250  1.0
  Sm  Sm1  1  0.250  0.963  0.523  1.0
  Sm  Sm2  1  0.250  0.963  0.977  1.0
  Sm  Sm3  1  0.250  0.463  0.023  1.0
  Sm  Sm4  1  0.250  0.463  0.477  1.0
  Sm  Sm5  1  0.485  0.298  0.750  1.0
  Sm  Sm6  1  0.515  0.702  0.250  1.0
  Sm  Sm7  1  0.750  0.537  0.523  1.0
  Sm  Sm8  1  0.750  0.537  0.977  1.0
  Sm  Sm9  1  0.750  0.037  0.023  1.0
  Sm  Sm10  1  0.750  0.037  0.477  1.0
  Sm  Sm11  1  0.985  0.202  0.750  1.0
  Nb  Nb12  1  0.996  0.746  0.750  1.0
  Nb  Nb13  1  0.504  0.246  0.250  1.0
  Nb  Nb14  1  0.496  0.754  0.750  1.0
  Nb  Nb15  1  0.004  0.254  0.250  1.0
  O  O16  1  0.036  0.049  0.126  1.0
  O  O17  1  0.036  0.049  0.374  1.0
  O  O18  1  0.041  0.592  0.612  1.0
  O  O19  1  0.041  0.592  0.888  1.0
  O  O20  1  0.248  0.332  0.250  1.0
  O  O21  1  0.257  0.732  0.117  1.0
  O  O22  1  0.257  0.732  0.383  1.0
  O  O23  1  0.243  0.232  0.617  1.0
  O  O24  1  0.243  0.232  0.883  1.0
  O  O25  1  0.252  0.832  0.750  1.0
  O  O26  1  0.459  0.092  0.112  1.0
  O  O27  1  0.459  0.092  0.388  1.0
  O  O28  1  0.464  0.549  0.626  1.0
  O  O29  1  0.464  0.549  0.874  1.0
  O  O30  1  0.536  0.451  0.126  1.0
  O  O31  1  0.536  0.451  0.374  1.0
  O  O32  1  0.541  0.908  0.612  1.0
  O  O33  1  0.541  0.908  0.888  1.0
  O  O34  1  0.748  0.168  0.250  1.0
  O  O35  1  0.757  0.768  0.117  1.0
  O  O36  1  0.757  0.768  0.383  1.0
  O  O37  1  0.743  0.268  0.617  1.0
  O  O38  1  0.743  0.268  0.883  1.0
  O  O39  1  0.752  0.668  0.750  1.0
  O  O40  1  0.959  0.408  0.112  1.0
  O  O41  1  0.959  0.408  0.388  1.0
  O  O42  1  0.964  0.951  0.626  1.0
  O  O43  1  0.964  0.951  0.874  1.0
[/CIF]
.
The crystal structure described by Sm3NbO7 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 Nb(1)O6 octahedra, corners with three equivalent Sm(2)O7 pentagonal bipyramids, edges with two equivalent Nb(1)O6 octahedra, and edges with two equivalent Sm(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles range from 32-44°. Nb(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form NbO6 octahedra that share corners with two equivalent Nb(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 37°. 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 Nb(1) atom to form distorted OSm3Nb tetrahedra that share corners with four equivalent O(4)Sm4 tetrahedra, edges with two equivalent O(1)Sm3Nb 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 Nb(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Sm(2) and two equivalent Nb(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)Sm3Nb tetrahedra, corners with six equivalent O(4)Sm4 tetrahedra,  an edgeedge with one O(4)Sm4 tetrahedra, and edges with two equivalent O(1)Sm3Nb tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Sm3NbO7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.604
_cell_length_b   7.723
_cell_length_c   10.832
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   636.103
_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  0.015  0.798  0.250  1.0
  Sm  Sm1  1  0.250  0.963  0.523  1.0
  Sm  Sm2  1  0.250  0.963  0.977  1.0
  Sm  Sm3  1  0.250  0.463  0.023  1.0
  Sm  Sm4  1  0.250  0.463  0.477  1.0
  Sm  Sm5  1  0.485  0.298  0.750  1.0
  Sm  Sm6  1  0.515  0.702  0.250  1.0
  Sm  Sm7  1  0.750  0.537  0.523  1.0
  Sm  Sm8  1  0.750  0.537  0.977  1.0
  Sm  Sm9  1  0.750  0.037  0.023  1.0
  Sm  Sm10  1  0.750  0.037  0.477  1.0
  Sm  Sm11  1  0.985  0.202  0.750  1.0
  Nb  Nb12  1  0.996  0.746  0.750  1.0
  Nb  Nb13  1  0.504  0.246  0.250  1.0
  Nb  Nb14  1  0.496  0.754  0.750  1.0
  Nb  Nb15  1  0.004  0.254  0.250  1.0
  O  O16  1  0.036  0.049  0.126  1.0
  O  O17  1  0.036  0.049  0.374  1.0
  O  O18  1  0.041  0.592  0.612  1.0
  O  O19  1  0.041  0.592  0.888  1.0
  O  O20  1  0.248  0.332  0.250  1.0
  O  O21  1  0.257  0.732  0.117  1.0
  O  O22  1  0.257  0.732  0.383  1.0
  O  O23  1  0.243  0.232  0.617  1.0
  O  O24  1  0.243  0.232  0.883  1.0
  O  O25  1  0.252  0.832  0.750  1.0
  O  O26  1  0.459  0.092  0.112  1.0
  O  O27  1  0.459  0.092  0.388  1.0
  O  O28  1  0.464  0.549  0.626  1.0
  O  O29  1  0.464  0.549  0.874  1.0
  O  O30  1  0.536  0.451  0.126  1.0
  O  O31  1  0.536  0.451  0.374  1.0
  O  O32  1  0.541  0.908  0.612  1.0
  O  O33  1  0.541  0.908  0.888  1.0
  O  O34  1  0.748  0.168  0.250  1.0
  O  O35  1  0.757  0.768  0.117  1.0
  O  O36  1  0.757  0.768  0.383  1.0
  O  O37  1  0.743  0.268  0.617  1.0
  O  O38  1  0.743  0.268  0.883  1.0
  O  O39  1  0.752  0.668  0.750  1.0
  O  O40  1  0.959  0.408  0.112  1.0
  O  O41  1  0.959  0.408  0.388  1.0
  O  O42  1  0.964  0.951  0.626  1.0
  O  O43  1  0.964  0.951  0.874  1.0
[/CIF]
.