data_CuAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.12
_cell_length_b   3.12
_cell_length_c   3.78
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CuAs
_chemical_formula_sum   'Cu1 As1'
_cell_volume   31.86
_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
  Cu  Cu1  1  0.0  0.0  0.0  1.0
  As  As0  1  1.0  0.8  0.89  1.0

data_CuAs
_symmetry_space_group_name_H-M   Cm
_cell_length_a   3.12
_cell_length_b   5.4
_cell_length_c   3.78
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   CuAs
_chemical_formula_sum   'Cu2 As2'
_cell_volume   63.73
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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
  Cu  Cu0  2  0.0  0.0  0.0  1.0
  As  As1  2  0.3  0.5  0.89  1.0

Cu As
Cu As 0 1 - - - 