The compound described by K7Ta(SO4)6 crystallizes in the trigonal R-3 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to six equivalent O(4) atoms to form distorted KO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and edges with six equivalent K(2)O6 octahedra. In the second K site, K(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form KO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with six equivalent S(1)O4 tetrahedra,  an edgeedge with one K(1)O6 octahedra, and edges with two equivalent K(2)O6 octahedra. The corner-sharing octahedral tilt angles are 75°. Ta(1) is bonded to six equivalent O(3) atoms to form TaO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra. S(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SO4 tetrahedra that share  a cornercorner with one K(1)O6 octahedra,  a cornercorner with one Ta(1)O6 octahedra, and corners with six equivalent K(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-66°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(2) and one S(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent K(2) and one S(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ta(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(1) atom. is represented by the CIF file [CIF]
data_K7Ta(SO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.293
_cell_length_b   9.293
_cell_length_c   9.293
_cell_angle_alpha   109.624
_cell_angle_beta   109.624
_cell_angle_gamma   109.624
_symmetry_Int_Tables_number   1
_cell_volume   614.234
_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
  K  K0  1  0.500  0.500  0.500  1.0
  K  K1  1  0.664  0.164  0.321  1.0
  K  K2  1  0.321  0.664  0.164  1.0
  K  K3  1  0.164  0.321  0.664  1.0
  K  K4  1  0.336  0.836  0.679  1.0
  K  K5  1  0.679  0.336  0.836  1.0
  K  K6  1  0.836  0.679  0.336  1.0
  Ta  Ta7  1  0.000  0.000  0.000  1.0
  S  S8  1  0.256  0.033  0.384  1.0
  S  S9  1  0.384  0.256  0.033  1.0
  S  S10  1  0.033  0.384  0.256  1.0
  S  S11  1  0.744  0.967  0.616  1.0
  S  S12  1  0.616  0.744  0.967  1.0
  S  S13  1  0.967  0.616  0.744  1.0
  O  O14  1  0.093  0.573  0.833  1.0
  O  O15  1  0.833  0.093  0.573  1.0
  O  O16  1  0.573  0.833  0.093  1.0
  O  O17  1  0.907  0.427  0.167  1.0
  O  O18  1  0.167  0.907  0.427  1.0
  O  O19  1  0.427  0.167  0.907  1.0
  O  O20  1  0.014  0.689  0.640  1.0
  O  O21  1  0.640  0.014  0.689  1.0
  O  O22  1  0.689  0.640  0.014  1.0
  O  O23  1  0.986  0.311  0.360  1.0
  O  O24  1  0.360  0.986  0.311  1.0
  O  O25  1  0.311  0.360  0.986  1.0
  O  O26  1  0.026  0.236  0.106  1.0
  O  O27  1  0.106  0.026  0.236  1.0
  O  O28  1  0.530  0.358  0.215  1.0
  O  O29  1  0.358  0.215  0.530  1.0
  O  O30  1  0.215  0.530  0.358  1.0
  O  O31  1  0.470  0.642  0.785  1.0
  O  O32  1  0.642  0.785  0.470  1.0
  O  O33  1  0.785  0.470  0.642  1.0
  O  O34  1  0.764  0.894  0.974  1.0
  O  O35  1  0.894  0.974  0.764  1.0
  O  O36  1  0.974  0.764  0.894  1.0
  O  O37  1  0.236  0.106  0.026  1.0
[/CIF]
.
The compound described by K7Ta(SO4)6 crystallizes in the trigonal R-3 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to six equivalent O(4) atoms to form distorted KO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra and edges with six equivalent K(2)O6 octahedra. In the second K site, K(2) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form KO6 octahedra that share corners with two equivalent K(2)O6 octahedra, corners with six equivalent S(1)O4 tetrahedra,  an edgeedge with one K(1)O6 octahedra, and edges with two equivalent K(2)O6 octahedra. The corner-sharing octahedral tilt angles are 75°. Ta(1) is bonded to six equivalent O(3) atoms to form TaO6 octahedra that share corners with six equivalent S(1)O4 tetrahedra. S(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form SO4 tetrahedra that share  a cornercorner with one K(1)O6 octahedra,  a cornercorner with one Ta(1)O6 octahedra, and corners with six equivalent K(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-66°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent K(2) and one S(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent K(2) and one S(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Ta(1) and one S(1) atom. In the fourth O site, O(4) is bonded in a distorted single-bond geometry to one K(1), two equivalent K(2), and one S(1) atom. is represented by the CIF file [CIF]
data_K7Ta(SO4)6
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.293
_cell_length_b   9.293
_cell_length_c   9.293
_cell_angle_alpha   109.624
_cell_angle_beta   109.624
_cell_angle_gamma   109.624
_symmetry_Int_Tables_number   1
_cell_volume   614.234
_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
  K  K0  1  0.500  0.500  0.500  1.0
  K  K1  1  0.664  0.164  0.321  1.0
  K  K2  1  0.321  0.664  0.164  1.0
  K  K3  1  0.164  0.321  0.664  1.0
  K  K4  1  0.336  0.836  0.679  1.0
  K  K5  1  0.679  0.336  0.836  1.0
  K  K6  1  0.836  0.679  0.336  1.0
  Ta  Ta7  1  0.000  0.000  0.000  1.0
  S  S8  1  0.256  0.033  0.384  1.0
  S  S9  1  0.384  0.256  0.033  1.0
  S  S10  1  0.033  0.384  0.256  1.0
  S  S11  1  0.744  0.967  0.616  1.0
  S  S12  1  0.616  0.744  0.967  1.0
  S  S13  1  0.967  0.616  0.744  1.0
  O  O14  1  0.093  0.573  0.833  1.0
  O  O15  1  0.833  0.093  0.573  1.0
  O  O16  1  0.573  0.833  0.093  1.0
  O  O17  1  0.907  0.427  0.167  1.0
  O  O18  1  0.167  0.907  0.427  1.0
  O  O19  1  0.427  0.167  0.907  1.0
  O  O20  1  0.014  0.689  0.640  1.0
  O  O21  1  0.640  0.014  0.689  1.0
  O  O22  1  0.689  0.640  0.014  1.0
  O  O23  1  0.986  0.311  0.360  1.0
  O  O24  1  0.360  0.986  0.311  1.0
  O  O25  1  0.311  0.360  0.986  1.0
  O  O26  1  0.026  0.236  0.106  1.0
  O  O27  1  0.106  0.026  0.236  1.0
  O  O28  1  0.530  0.358  0.215  1.0
  O  O29  1  0.358  0.215  0.530  1.0
  O  O30  1  0.215  0.530  0.358  1.0
  O  O31  1  0.470  0.642  0.785  1.0
  O  O32  1  0.642  0.785  0.470  1.0
  O  O33  1  0.785  0.470  0.642  1.0
  O  O34  1  0.764  0.894  0.974  1.0
  O  O35  1  0.894  0.974  0.764  1.0
  O  O36  1  0.974  0.764  0.894  1.0
  O  O37  1  0.236  0.106  0.026  1.0
[/CIF]
.