data_Ca3As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.8
_cell_length_b   3.8
_cell_length_c   9.11
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ca3As
_chemical_formula_sum   'Ca3 As1'
_cell_volume   131.76
_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
  Ca  Ca1  1  0.9  0.9  0.02  1.0
  Ca  Ca2  1  0.0  0.0  0.0  1.0
  Ca  Ca3  1  0.9  0.9  0.09  1.0
  As  As0  1  0.0  0.0  0.55  1.0

data_Ca3As
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.38
_cell_length_b   5.38
_cell_length_c   9.11
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Ca3As
_chemical_formula_sum   'Ca6 As2'
_cell_volume   263.52
_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
  Ca  Ca0  2  0.0  0.0  0.0  1.0
  Ca  Ca1  2  0.4  0.5  0.02  1.0
  Ca  Ca2  2  0.4  0.5  0.09  1.0
  As  As3  2  0.0  0.0  0.55  1.0

Ca Ca Ca As
Ca Ca Ca As 0 1 + + o 0 2 o o o 0 3 + + - 1 3 o o - 2 3 + + o 3 3 + o o 3 3 o + o 