data_SrCu2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.4
_cell_length_b   3.4
_cell_length_c   6.89
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrCu2As
_chemical_formula_sum   'Sr1 Cu2 As1'
_cell_volume   79.62
_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
  Sr  Sr3  1  0.7  0.7  0.42  1.0
  Cu  Cu1  1  0.7  0.7  0.03  1.0
  Cu  Cu2  1  0.0  0.0  0.21  1.0
  As  As0  1  0.0  0.0  0.68  1.0

data_SrCu2As
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.81
_cell_length_b   4.81
_cell_length_c   6.89
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   SrCu2As
_chemical_formula_sum   'Sr2 Cu4 As2'
_cell_volume   159.25
_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
  Sr  Sr0  2  0.2  0.5  0.42  1.0
  Cu  Cu1  2  0.0  0.0  0.21  1.0
  Cu  Cu2  2  0.2  0.5  0.03  1.0
  As  As3  2  0.0  0.0  0.68  1.0

Sr Cu Cu As
Sr Cu Cu As 0 2 + + o 0 3 + + o 1 2 + + o 
SrCu2As crystallizes in the monoclinic Cm space group. Sr(1) is bonded in a distorted L-shaped geometry to one Cu(1), one Cu(2), and one As(1) atom. The Sr(1)-Cu(1) bond length is 2.67 Å. The Sr(1)-Cu(2) bond length is 2.01 Å. The Sr(1)-As(1) bond length is 2.30 Å. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a 5-coordinate geometry to one Sr(1), three equivalent Cu(2), and one As(1) atom. There is one shorter (1.93 Å) and two longer (2.89 Å) Cu(1)-Cu(2) bond lengths. The Cu(1)-As(1) bond length is 2.83 Å. In the second Cu site, Cu(2) is bonded in a distorted single-bond geometry to one Sr(1) and three equivalent Cu(1) atoms. As(1) is bonded in a distorted single-bond geometry to one Sr(1) and one Cu(1) atom.