data_Ag2Se
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.04
_cell_length_b   6.79
_cell_length_c   6.86
_cell_angle_alpha   76.59
_cell_angle_beta   85.04
_cell_angle_gamma   88.89
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Ag2Se
_chemical_formula_sum   'Ag8 Se4'
_cell_volume   227.39
_cell_formula_units_Z   4
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
  Ag  Ag0  1  0.41  0.28  0.12  1.0
  Ag  Ag1  1  0.1  0.14  0.73  1.0
  Ag  Ag2  1  0.36  0.09  0.52  1.0
  Ag  Ag3  1  0.66  0.22  0.91  1.0
  Ag  Ag4  1  0.2  0.89  0.02  1.0
  Ag  Ag5  1  0.85  0.64  0.7  1.0
  Ag  Ag6  1  0.57  0.47  0.62  1.0
  Ag  Ag7  1  0.91  0.73  0.94  1.0
  Se  Se8  1  0.81  0.89  0.27  1.0
  Se  Se9  1  0.54  0.04  0.92  1.0
  Se  Se10  1  0.96  0.47  0.38  1.0
  Se  Se11  1  0.23  0.33  0.73  1.0

data_Ag2Se
_symmetry_space_group_name_H-M   P-1
_cell_length_a   5.04
_cell_length_b   6.79
_cell_length_c   6.86
_cell_angle_alpha   76.59
_cell_angle_beta   85.04
_cell_angle_gamma   88.89
_symmetry_Int_Tables_number   2
_chemical_formula_structural   Ag2Se
_chemical_formula_sum   'Ag8 Se4'
_cell_volume   227.39
_cell_formula_units_Z   4
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-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
  Ag  Ag0  2  0.03  0.09  0.8  1.0
  Ag  Ag1  2  0.19  0.29  0.3  1.0
  Ag  Ag2  2  0.28  0.04  0.59  1.0
  Ag  Ag3  2  0.47  0.45  0.38  1.0
  Se  Se4  2  0.16  0.85  0.59  1.0
  Se  Se5  2  0.43  0.71  0.94  1.0

Ag Ag Ag Ag Ag Ag Ag Ag Se Se Se Se
Ag Ag Ag Ag Ag Ag Ag Ag Se Se Se Se 0 3 o o - 0 10 - o o 1 11 o o o 1 2 o o o 1 4 o - + 1 10 - o o 2 8 o - o 3 9 o o o 3 6 o o o 3 8 o - + 4 7 - o - 4 9 o + - 4 8 - o o 5 6 o o o 5 7 o o o 5 8 o o o 5 10 o o o 6 11 o o o 6 10 o o o 7 8 o o + 7 10 o o + 8 9 o + - 8 10 o o o 10 11 + o o 
Ag2Se crystallizes in the triclinic P-1 space group. There are four inequivalent Ag sites. In the first Ag site, Ag(1) is bonded in a 5-coordinate geometry to one Ag(1), one Ag(2), one Se(1), and two equivalent Se(2) atoms. The Ag(1)-Ag(1) bond length is 2.73 Å. The Ag(1)-Ag(2) bond length is 1.93 Å. The Ag(1)-Se(1) bond length is 3.21 Å. There is one shorter (2.44 Å) and one longer (2.88 Å) Ag(1)-Se(2) bond length. In the second Ag site, Ag(2) is bonded in a single-bond geometry to one Ag(1) and one Se(2) atom. The Ag(2)-Se(2) bond length is 1.42 Å. In the third Ag site, Ag(3) is bonded in a 1-coordinate geometry to one Ag(4), one Se(1), and one Se(2) atom. The Ag(3)-Ag(4) bond length is 1.99 Å. The Ag(3)-Se(1) bond length is 2.44 Å. The Ag(3)-Se(2) bond length is 2.01 Å. In the fourth Ag site, Ag(4) is bonded in a 5-coordinate geometry to one Ag(3), one Ag(4), one Se(2), and two equivalent Se(1) atoms. The Ag(4)-Ag(4) bond length is 1.96 Å. The Ag(4)-Se(2) bond length is 2.77 Å. There is one shorter (2.71 Å) and one longer (3.11 Å) Ag(4)-Se(1) bond length. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 1-coordinate geometry to one Ag(1), one Ag(3), and two equivalent Ag(4) atoms. In the second Se site, Se(2) is bonded in a 1-coordinate geometry to one Ag(2), one Ag(3), one Ag(4), and two equivalent Ag(1) atoms.