data_K2AlB
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   5.07
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K2AlB
_chemical_formula_sum   'K2 Al1 B1'
_cell_volume   92.39
_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  K2  1  0.38  0.38  0.38  1.0
  K  K3  1  0.59  0.59  0.59  1.0
  Al  Al0  1  0.79  0.79  0.79  1.0
  B  B1  1  0.0  0.0  0.0  1.0

data_K2AlB
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.07
_cell_length_b   5.07
_cell_length_c   12.43
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   K2AlB
_chemical_formula_sum   'K6 Al3 B3'
_cell_volume   277.17
_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  3  0.0  0.0  0.41  1.0
  K  K1  3  0.0  0.0  0.62  1.0
  Al  Al2  3  0.0  0.0  0.21  1.0
  B  B3  3  0.0  0.0  0.0  1.0

K K Al B
K2AlB crystallizes in the trigonal R3m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 7-coordinate geometry to one K(2), three equivalent Al(1), and three equivalent B(1) atoms. The K(1)-K(2) bond length is 2.56 Å. All K(1)-Al(1) bond lengths are 3.09 Å. All K(1)-B(1) bond lengths are 2.99 Å. In the second K site, K(2) is bonded in a 1-coordinate geometry to one K(1), four equivalent Al(1), and three equivalent B(1) atoms. There is one shorter (2.56 Å) and three longer (3.33 Å) K(2)-Al(1) bond lengths. All K(2)-B(1) bond lengths are 3.09 Å. Al(1) is bonded in a 8-coordinate geometry to three equivalent K(1), four equivalent K(2), and one B(1) atom. The Al(1)-B(1) bond length is 2.56 Å. B(1) is bonded to three equivalent K(1), three equivalent K(2), and one Al(1) atom to form distorted edge-sharing BK6Al hexagonal pyramids.