data_K4BeSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.13
_cell_length_b   7.13
_cell_length_c   7.13
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   K4BeSe
_chemical_formula_sum   'K4 Be1 Se1'
_cell_volume   256.19
_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  K1  1  0.29  0.29  0.79  1.0
  K  K2  1  0.29  0.79  0.29  1.0
  K  K3  1  0.79  0.29  0.29  1.0
  K  K4  1  0.79  0.79  0.79  1.0
  Be  Be0  1  0.0  0.0  0.0  1.0
  Se  Se5  1  0.56  0.56  0.56  1.0

data_K4BeSe
_symmetry_space_group_name_H-M   R3m
_cell_length_a   7.13
_cell_length_b   7.13
_cell_length_c   17.46
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   K4BeSe
_chemical_formula_sum   'K12 Be3 Se3'
_cell_volume   768.57
_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  0.0  0.5  0.21  1.0
  K  K1  3  0.0  0.0  0.21  1.0
  Be  Be2  3  0.0  0.0  0.0  1.0
  Se  Se3  3  0.0  0.0  0.44  1.0

K K K K Be Se
K K K K Be Se 0 4 o o + 0 1 o - + 0 1 o o o 0 3 - o o 0 3 o - o 0 2 - o + 0 2 o o o 0 5 o o o 1 4 o + o 1 2 - + o 1 2 o o o 1 3 - o o 1 3 o o - 1 5 o o o 2 3 o - o 2 3 o o - 2 5 o o o 2 4 + o o 3 5 o o o 3 4 + + + 
K4BeSe crystallizes in the trigonal R3m space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a distorted linear geometry to two equivalent K(2), one Be(1), and one Se(1) atom. Both K(1)-K(2) bond lengths are 3.57 Å. The K(1)-Be(1) bond length is 3.02 Å. The K(1)-Se(1) bond length is 2.71 Å. In the second K site, K(2) is bonded to six equivalent K(1), one Be(1), and one Se(1) atom to form distorted corner-sharing KK6BeSe hexagonal bipyramids. The K(2)-Be(1) bond length is 3.70 Å. The K(2)-Se(1) bond length is 3.96 Å. Be(1) is bonded in a 4-coordinate geometry to one K(2) and three equivalent K(1) atoms. Se(1) is bonded in a 3-coordinate geometry to one K(2) and three equivalent K(1) atoms.