data_K3RbTa
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.9
_cell_length_b   6.9
_cell_length_c   6.9
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K3RbTa
_chemical_formula_sum   'K3 Rb1 Ta1'
_cell_volume   328.5
_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  0.0  0.45  0.0  1.0
  K  K1  1  0.0  0.0  0.45  1.0
  K  K2  1  0.45  0.0  0.0  1.0
  Rb  Rb3  1  0.0  0.0  0.0  1.0
  Ta  Ta4  1  0.45  0.45  0.45  1.0

data_K3RbTa
_symmetry_space_group_name_H-M   R3m
_cell_length_a   9.76
_cell_length_b   9.76
_cell_length_c   11.95
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   K3RbTa
_chemical_formula_sum   'K9 Rb3 Ta3'
_cell_volume   985.49
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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  9  0.18  0.37  0.82  1.0
  Rb  Rb1  3  0.0  0.0  0.0  1.0
  Ta  Ta2  3  0.0  0.0  0.45  1.0

K K K Rb Ta
RbK3Ta is (Cubic) Perovskite structured and crystallizes in the trigonal R3m space group. Rb(1) is bonded to six equivalent K(1) atoms to form corner-sharing RbK6 octahedra. The corner-sharing octahedra are not tilted. There are three shorter (3.10 Å) and three longer (3.80 Å) Rb(1)-K(1) bond lengths. K(1) is bonded in a distorted T-shaped geometry to two equivalent Rb(1) and one Ta(1) atom. The K(1)-Ta(1) bond length is 4.39 Å. Ta(1) is bonded in a 3-coordinate geometry to three equivalent K(1) atoms.