The crystal structure described by Rb3TaO8 crystallizes in the tetragonal I-42m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to four equivalent O(1) and four equivalent O(2) atoms to form RbO8 hexagonal bipyramids that share corners with four equivalent Ta(1)O8 hexagonal bipyramids, corners with four equivalent O(2)Rb3TaO trigonal bipyramids, and edges with two equivalent Ta(1)O8 hexagonal bipyramids. In the second Rb site, Rb(2) is bonded in a 12-coordinate geometry to four equivalent O(2) and eight equivalent O(1) atoms. Ta(1) is bonded to four equivalent O(1) and four equivalent O(2) atoms to form distorted TaO8 hexagonal bipyramids that share corners with four equivalent Rb(1)O8 hexagonal bipyramids, corners with four equivalent O(2)Rb3TaO trigonal bipyramids, and edges with two equivalent Rb(1)O8 hexagonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one Rb(1), four equivalent Rb(2), one Ta(1), and one O(2) atom. In the second O site, O(2) is bonded to one Rb(1), two equivalent Rb(2), one Ta(1), and one O(1) atom to form distorted ORb3TaO trigonal bipyramids that share  a cornercorner with one Rb(1)O8 hexagonal bipyramid,  a cornercorner with one Ta(1)O8 hexagonal bipyramid, corners with ten equivalent O(2)Rb3TaO trigonal bipyramids, and  an edgeedge with one O(2)Rb3TaO trigonal bipyramid. is represented by the CIF card [CIF]
data_Rb3TaO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.412
_cell_length_b   6.412
_cell_length_c   6.412
_cell_angle_alpha   102.899
_cell_angle_beta   112.854
_cell_angle_gamma   112.854
_symmetry_Int_Tables_number   1
_cell_volume   200.955
_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
  Rb  Rb0  1  0.000  0.500  0.500  1.0
  Rb  Rb1  1  0.500  0.250  0.750  1.0
  Rb  Rb2  1  0.500  0.750  0.250  1.0
  Ta  Ta3  1  0.000  0.000  0.000  1.0
  O  O4  1  0.590  0.813  0.813  1.0
  O  O5  1  0.000  0.187  0.777  1.0
  O  O6  1  0.000  0.777  0.187  1.0
  O  O7  1  0.410  0.223  0.223  1.0
  O  O8  1  0.271  0.320  0.320  1.0
  O  O9  1  0.000  0.680  0.950  1.0
  O  O10  1  0.000  0.950  0.680  1.0
  O  O11  1  0.729  0.050  0.050  1.0
[/CIF]
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The crystal structure described by Rb3TaO8 crystallizes in the tetragonal I-42m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded to four equivalent O(1) and four equivalent O(2) atoms to form RbO8 hexagonal bipyramids that share corners with four equivalent Ta(1)O8 hexagonal bipyramids, corners with four equivalent O(2)Rb3TaO trigonal bipyramids, and edges with two equivalent Ta(1)O8 hexagonal bipyramids. In the second Rb site, Rb(2) is bonded in a 12-coordinate geometry to four equivalent O(2) and eight equivalent O(1) atoms. Ta(1) is bonded to four equivalent O(1) and four equivalent O(2) atoms to form distorted TaO8 hexagonal bipyramids that share corners with four equivalent Rb(1)O8 hexagonal bipyramids, corners with four equivalent O(2)Rb3TaO trigonal bipyramids, and edges with two equivalent Rb(1)O8 hexagonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded in a 7-coordinate geometry to one Rb(1), four equivalent Rb(2), one Ta(1), and one O(2) atom. In the second O site, O(2) is bonded to one Rb(1), two equivalent Rb(2), one Ta(1), and one O(1) atom to form distorted ORb3TaO trigonal bipyramids that share  a cornercorner with one Rb(1)O8 hexagonal bipyramid,  a cornercorner with one Ta(1)O8 hexagonal bipyramid, corners with ten equivalent O(2)Rb3TaO trigonal bipyramids, and  an edgeedge with one O(2)Rb3TaO trigonal bipyramid. is represented by the CIF card [CIF]
data_Rb3TaO8
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.412
_cell_length_b   6.412
_cell_length_c   6.412
_cell_angle_alpha   102.899
_cell_angle_beta   112.854
_cell_angle_gamma   112.854
_symmetry_Int_Tables_number   1
_cell_volume   200.955
_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
  Rb  Rb0  1  0.000  0.500  0.500  1.0
  Rb  Rb1  1  0.500  0.250  0.750  1.0
  Rb  Rb2  1  0.500  0.750  0.250  1.0
  Ta  Ta3  1  0.000  0.000  0.000  1.0
  O  O4  1  0.590  0.813  0.813  1.0
  O  O5  1  0.000  0.187  0.777  1.0
  O  O6  1  0.000  0.777  0.187  1.0
  O  O7  1  0.410  0.223  0.223  1.0
  O  O8  1  0.271  0.320  0.320  1.0
  O  O9  1  0.000  0.680  0.950  1.0
  O  O10  1  0.000  0.950  0.680  1.0
  O  O11  1  0.729  0.050  0.050  1.0
[/CIF]
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