data_ZnCu2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.76
_cell_length_b   2.76
_cell_length_c   7.75
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   ZnCu2As
_chemical_formula_sum   'Zn1 Cu2 As1'
_cell_volume   59.1
_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
  Zn  Zn3  1  0.0  0.0  0.55  1.0
  Cu  Cu1  1  0.0  0.0  0.18  1.0
  Cu  Cu2  1  0.38  0.38  0.87  1.0
  As  As0  1  0.38  0.38  0.03  1.0

data_ZnCu2As
_symmetry_space_group_name_H-M   Cm
_cell_length_a   3.9
_cell_length_b   3.9
_cell_length_c   7.75
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   ZnCu2As
_chemical_formula_sum   'Zn2 Cu4 As2'
_cell_volume   118.19
_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
  Zn  Zn0  2  0.0  0.0  0.55  1.0
  Cu  Cu1  2  0.0  0.0  0.18  1.0
  Cu  Cu2  2  0.38  0.0  0.87  1.0
  As  As3  2  0.38  0.0  0.03  1.0

Zn Cu Cu As
Cu2ZnAs crystallizes in the monoclinic Cm space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 1-coordinate geometry to one Zn(1) and one As(1) atom. The Cu(1)-Zn(1) bond length is 2.93 Å. The Cu(1)-As(1) bond length is 1.87 Å. In the second Cu site, Cu(2) is bonded in a single-bond geometry to three equivalent Zn(1) and one As(1) atom. There is one shorter (2.83 Å) and two longer (3.14 Å) Cu(2)-Zn(1) bond lengths. The Cu(2)-As(1) bond length is 1.27 Å. Zn(1) is bonded in a 8-coordinate geometry to one Cu(1), three equivalent Cu(2), and four equivalent Zn(1) atoms. All Zn(1)-Zn(1) bond lengths are 2.76 Å. As(1) is bonded in a 2-coordinate geometry to one Cu(1) and one Cu(2) atom.