data_GaCu2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.41
_cell_length_b   4.41
_cell_length_c   4.41
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   GaCu2As
_chemical_formula_sum   'Ga1 Cu2 As1'
_cell_volume   60.47
_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
  Ga  Ga3  1  0.0  0.0  0.0  1.0
  Cu  Cu1  1  0.67  0.67  0.67  1.0
  Cu  Cu2  1  0.56  0.56  0.56  1.0
  As  As0  1  0.12  0.12  0.12  1.0

data_GaCu2As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.41
_cell_length_b   4.41
_cell_length_c   10.79
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   GaCu2As
_chemical_formula_sum   'Ga3 Cu6 As3'
_cell_volume   181.42
_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
  Ga  Ga0  3  0.0  0.0  0.0  1.0
  Cu  Cu1  3  0.0  0.0  0.33  1.0
  Cu  Cu2  3  0.0  0.0  0.44  1.0
  As  As3  3  0.0  0.0  0.88  1.0

Ga Cu Cu As
Ga Cu Cu As 0 3 o o o 1 2 o o o 
(Cu)2GaAs is Halite, Rock Salt structured and crystallizes in the trigonal R3m space group. The structure is zero-dimensional and consists of three gallium arsenide molecules and three Cu clusters. In each Cu cluster, there are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a distorted single-bond geometry to one Cu(2) atom. The Cu(1)-Cu(2) bond length is 1.25 Å. In the second Cu site, Cu(2) is bonded in a distorted single-bond geometry to one Cu(1) atom.