The structure described by Sm2Ta2Cl2O7 crystallizes in the monoclinic C2/m space group. Sm(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), three equivalent O(4), and three equivalent Cl(1) atoms. Ta(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Sm(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to two equivalent Sm(1) and two equivalent Ta(1) atoms to form distorted OSm2Ta2 trigonal pyramids that share corners with five equivalent O(4)Sm3Ta tetrahedra, corners with two equivalent O(2)Sm2Ta2 trigonal pyramids,  an edgeedge with one O(2)Sm2Ta2 trigonal pyramid, and  a faceface with one O(4)Sm3Ta tetrahedra. 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 to three equivalent Sm(1) and one Ta(1) atom to form distorted OSm3Ta tetrahedra that share corners with two equivalent O(4)Sm3Ta tetrahedra, corners with five equivalent O(2)Sm2Ta2 trigonal pyramids, edges with two equivalent O(4)Sm3Ta tetrahedra, and  a faceface with one O(2)Sm2Ta2 trigonal pyramid. Cl(1) is bonded in a trigonal non-coplanar geometry to three equivalent Sm(1) atoms. is represented by the CIF card [CIF]
data_Sm2Ta2Cl2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.978
_cell_length_b   7.978
_cell_length_c   6.921
_cell_angle_alpha   66.831
_cell_angle_beta   66.831
_cell_angle_gamma   28.570
_symmetry_Int_Tables_number   1
_cell_volume   192.522
_cell_formula_units_Z   1
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  0.307  0.307  0.163  1.0
  Sm  Sm1  1  0.693  0.693  0.837  1.0
  Ta  Ta2  1  0.965  0.965  0.800  1.0
  Ta  Ta3  1  0.035  0.035  0.200  1.0
  Cl  Cl4  1  0.680  0.680  0.434  1.0
  Cl  Cl5  1  0.320  0.320  0.566  1.0
  O  O6  1  0.453  0.453  0.840  1.0
  O  O7  1  0.547  0.547  0.160  1.0
  O  O8  1  0.918  0.918  0.154  1.0
  O  O9  1  0.000  0.000  0.500  1.0
  O  O10  1  0.824  0.824  0.933  1.0
  O  O11  1  0.082  0.082  0.846  1.0
  O  O12  1  0.176  0.176  0.067  1.0
[/CIF]
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The structure described by Sm2Ta2Cl2O7 crystallizes in the monoclinic C2/m space group. Sm(1) is bonded in a 9-coordinate geometry to one O(1), two equivalent O(2), three equivalent O(4), and three equivalent Cl(1) atoms. Ta(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form a mixture of distorted edge and corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles range from 0-15°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Sm(1) and two equivalent Ta(1) atoms. In the second O site, O(2) is bonded to two equivalent Sm(1) and two equivalent Ta(1) atoms to form distorted OSm2Ta2 trigonal pyramids that share corners with five equivalent O(4)Sm3Ta tetrahedra, corners with two equivalent O(2)Sm2Ta2 trigonal pyramids,  an edgeedge with one O(2)Sm2Ta2 trigonal pyramid, and  a faceface with one O(4)Sm3Ta tetrahedra. 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 to three equivalent Sm(1) and one Ta(1) atom to form distorted OSm3Ta tetrahedra that share corners with two equivalent O(4)Sm3Ta tetrahedra, corners with five equivalent O(2)Sm2Ta2 trigonal pyramids, edges with two equivalent O(4)Sm3Ta tetrahedra, and  a faceface with one O(2)Sm2Ta2 trigonal pyramid. Cl(1) is bonded in a trigonal non-coplanar geometry to three equivalent Sm(1) atoms. is represented by the CIF card [CIF]
data_Sm2Ta2Cl2O7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.978
_cell_length_b   7.978
_cell_length_c   6.921
_cell_angle_alpha   66.831
_cell_angle_beta   66.831
_cell_angle_gamma   28.570
_symmetry_Int_Tables_number   1
_cell_volume   192.522
_cell_formula_units_Z   1
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  0.307  0.307  0.163  1.0
  Sm  Sm1  1  0.693  0.693  0.837  1.0
  Ta  Ta2  1  0.965  0.965  0.800  1.0
  Ta  Ta3  1  0.035  0.035  0.200  1.0
  Cl  Cl4  1  0.680  0.680  0.434  1.0
  Cl  Cl5  1  0.320  0.320  0.566  1.0
  O  O6  1  0.453  0.453  0.840  1.0
  O  O7  1  0.547  0.547  0.160  1.0
  O  O8  1  0.918  0.918  0.154  1.0
  O  O9  1  0.000  0.000  0.500  1.0
  O  O10  1  0.824  0.824  0.933  1.0
  O  O11  1  0.082  0.082  0.846  1.0
  O  O12  1  0.176  0.176  0.067  1.0
[/CIF]
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