data_CsBe3As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.86
_cell_length_b   4.86
_cell_length_c   4.86
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CsBe3As
_chemical_formula_sum   'Cs1 Be3 As1'
_cell_volume   114.86
_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
  Cs  Cs0  1  0.43  0.43  0.43  1.0
  Be  Be1  1  0.0  0.43  0.0  1.0
  Be  Be2  1  0.0  0.0  0.43  1.0
  Be  Be3  1  0.43  0.0  0.0  1.0
  As  As4  1  0.0  0.0  0.0  1.0

data_CsBe3As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.87
_cell_length_b   6.87
_cell_length_c   8.42
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   CsBe3As
_chemical_formula_sum   'Cs3 Be9 As3'
_cell_volume   344.59
_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
  Cs  Cs0  3  0.0  0.0  0.43  1.0
  Be  Be1  9  0.19  0.38  0.81  1.0
  As  As2  3  0.0  0.0  0.0  1.0

Cs Be Be Be As
Cs Be Be Be As 0 4 o o o 0 2 o o o 0 2 o + o 0 2 + o o 0 1 o o o 0 1 o o + 0 1 + o o 0 3 o o o 0 3 o o + 0 3 o + o 1 4 o o o 2 4 o o o 3 4 o o o 
CsBe3As crystallizes in the trigonal R3m space group. Cs(1) is bonded to twelve equivalent Be(1) atoms to form distorted CsBe12 cuboctahedra that share corners with twelve equivalent Cs(1)Be12 cuboctahedra, faces with six equivalent Cs(1)Be12 cuboctahedra, and faces with eight equivalent As(1)Be6 octahedra. There are a spread of Cs(1)-Be(1) bond distances ranging from 2.96-3.91 Å. Be(1) is bonded in a distorted single-bond geometry to four equivalent Cs(1) and two equivalent As(1) atoms. There is one shorter (2.09 Å) and one longer (2.77 Å) Be(1)-As(1) bond length. As(1) is bonded to six equivalent Be(1) atoms to form distorted AsBe6 octahedra that share corners with six equivalent As(1)Be6 octahedra and faces with eight equivalent Cs(1)Be12 cuboctahedra. The corner-sharing octahedra are not tilted.