The crystal structure described by Sm2Ta2O9 crystallizes in the monoclinic P2_1/c space group. Sm(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(1), three equivalent O(2), and three equivalent O(5) atoms. Ta(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing OSm2Ta2 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Sm(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Sm(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Sm(1) and one Ta(1) atom. is represented by the CIF file [CIF]
data_Sm2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.879
_cell_length_b   6.684
_cell_length_c   15.485
_cell_angle_alpha   67.327
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   370.493
_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
  Sm  Sm0  1  0.996  0.687  0.304  1.0
  Sm  Sm1  1  0.004  0.313  0.696  1.0
  Sm  Sm2  1  0.496  0.313  0.196  1.0
  Sm  Sm3  1  0.504  0.687  0.804  1.0
  Ta  Ta4  1  0.997  0.693  0.040  1.0
  Ta  Ta5  1  0.003  0.307  0.960  1.0
  Ta  Ta6  1  0.497  0.307  0.460  1.0
  Ta  Ta7  1  0.503  0.693  0.540  1.0
  O  O8  1  0.999  0.339  0.083  1.0
  O  O9  1  0.001  0.661  0.917  1.0
  O  O10  1  0.499  0.661  0.417  1.0
  O  O11  1  0.501  0.339  0.583  1.0
  O  O12  1  0.491  0.941  0.218  1.0
  O  O13  1  0.509  0.059  0.782  1.0
  O  O14  1  0.991  0.059  0.282  1.0
  O  O15  1  0.009  0.941  0.718  1.0
  O  O16  1  0.000  0.000  0.000  1.0
  O  O17  1  0.500  0.000  0.500  1.0
  O  O18  1  0.498  0.652  0.050  1.0
  O  O19  1  0.502  0.348  0.950  1.0
  O  O20  1  0.998  0.348  0.450  1.0
  O  O21  1  0.002  0.652  0.550  1.0
  O  O22  1  0.997  0.578  0.178  1.0
  O  O23  1  0.003  0.422  0.822  1.0
  O  O24  1  0.497  0.422  0.322  1.0
  O  O25  1  0.503  0.578  0.678  1.0
[/CIF]
.
The crystal structure described by Sm2Ta2O9 crystallizes in the monoclinic P2_1/c space group. Sm(1) is bonded in a 9-coordinate geometry to one O(4), two equivalent O(1), three equivalent O(2), and three equivalent O(5) atoms. Ta(1) is bonded to one O(3), one O(5), two equivalent O(1), and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. There are five inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Sm(1) and two equivalent Ta(1) atoms to form a mixture of distorted corner and edge-sharing OSm2Ta2 trigonal pyramids. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to three equivalent Sm(1) atoms. In the third O site, O(3) is bonded in a linear geometry to two equivalent Ta(1) atoms. In the fourth O site, O(4) is bonded in a distorted T-shaped geometry to one Sm(1) and two equivalent Ta(1) atoms. In the fifth O site, O(5) is bonded in a 4-coordinate geometry to three equivalent Sm(1) and one Ta(1) atom. is represented by the CIF file [CIF]
data_Sm2Ta2O9
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.879
_cell_length_b   6.684
_cell_length_c   15.485
_cell_angle_alpha   67.327
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   370.493
_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
  Sm  Sm0  1  0.996  0.687  0.304  1.0
  Sm  Sm1  1  0.004  0.313  0.696  1.0
  Sm  Sm2  1  0.496  0.313  0.196  1.0
  Sm  Sm3  1  0.504  0.687  0.804  1.0
  Ta  Ta4  1  0.997  0.693  0.040  1.0
  Ta  Ta5  1  0.003  0.307  0.960  1.0
  Ta  Ta6  1  0.497  0.307  0.460  1.0
  Ta  Ta7  1  0.503  0.693  0.540  1.0
  O  O8  1  0.999  0.339  0.083  1.0
  O  O9  1  0.001  0.661  0.917  1.0
  O  O10  1  0.499  0.661  0.417  1.0
  O  O11  1  0.501  0.339  0.583  1.0
  O  O12  1  0.491  0.941  0.218  1.0
  O  O13  1  0.509  0.059  0.782  1.0
  O  O14  1  0.991  0.059  0.282  1.0
  O  O15  1  0.009  0.941  0.718  1.0
  O  O16  1  0.000  0.000  0.000  1.0
  O  O17  1  0.500  0.000  0.500  1.0
  O  O18  1  0.498  0.652  0.050  1.0
  O  O19  1  0.502  0.348  0.950  1.0
  O  O20  1  0.998  0.348  0.450  1.0
  O  O21  1  0.002  0.652  0.550  1.0
  O  O22  1  0.997  0.578  0.178  1.0
  O  O23  1  0.003  0.422  0.822  1.0
  O  O24  1  0.497  0.422  0.322  1.0
  O  O25  1  0.503  0.578  0.678  1.0
[/CIF]
.