data_KB3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.92
_cell_length_b   4.92
_cell_length_c   4.92
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KB3
_chemical_formula_sum   'K2 B6'
_cell_volume   119.09
_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
  K  K6  1  0.46  0.46  0.46  1.0
  K  K7  1  0.0  0.0  0.0  1.0
  B  B0  1  0.23  0.0  0.46  1.0
  B  B1  1  0.69  0.0  0.46  1.0
  B  B2  1  0.46  0.23  0.0  1.0
  B  B3  1  0.46  0.69  0.0  1.0
  B  B4  1  0.0  0.46  0.69  1.0
  B  B5  1  0.0  0.46  0.23  1.0

data_KB3
_symmetry_space_group_name_H-M   R3
_cell_length_a   6.96
_cell_length_b   6.96
_cell_length_c   8.52
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   146
_chemical_formula_structural   KB3
_chemical_formula_sum   'K6 B18'
_cell_volume   357.28
_cell_formula_units_Z   6
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  'x+1/3, y+2/3, z+2/3'
  5  '-y+1/3, x-y+2/3, z+2/3'
  6  '-x+y+1/3, -x+2/3, z+2/3'
  7  'x+2/3, y+1/3, z+1/3'
  8  '-y+2/3, x-y+1/3, z+1/3'
  9  '-x+y+2/3, -x+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  3  0.0  0.0  0.0  1.0
  K  K1  3  0.0  0.0  0.46  1.0
  B  B2  9  0.0  0.77  0.23  1.0
  B  B3  9  0.08  0.38  0.38  1.0

K K B B B B B B
KB3 crystallizes in the trigonal R3 space group. There are two inequivalent K sites. In the first K site, K(1) is bonded to six equivalent B(1) and six equivalent B(2) atoms to form a mixture of edge and face-sharing KB12 cuboctahedra. There are three shorter (2.53 Å) and three longer (2.89 Å) K(1)-B(1) bond lengths. There are three shorter (2.53 Å) and three longer (2.89 Å) K(1)-B(2) bond lengths. In the second K site, K(2) is bonded to six equivalent B(1) and six equivalent B(2) atoms to form a mixture of distorted edge and face-sharing KB12 cuboctahedra. There are three shorter (2.53 Å) and three longer (2.89 Å) K(2)-B(1) bond lengths. There are three shorter (2.73 Å) and three longer (3.06 Å) K(2)-B(2) bond lengths. There are two inequivalent B sites. In the first B site, B(1) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one B(2) atom. The B(1)-B(2) bond length is 2.26 Å. In the second B site, B(2) is bonded in a 5-coordinate geometry to two equivalent K(1), two equivalent K(2), and one B(1) atom.