data_CrSiSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.04
_cell_length_b   3.04
_cell_length_c   6.96
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   91.45
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CrSiSe2
_chemical_formula_sum   'Cr1 Si1 Se2'
_cell_volume   64.37
_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
  Cr  Cr0  1  0.0  0.0  0.48  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.12  0.0  0.95  1.0
  Se  Se2  1  0.12  0.0  0.01  1.0

data_CrSiSe2
_symmetry_space_group_name_H-M   Pm
_cell_length_a   3.04
_cell_length_b   3.04
_cell_length_c   6.96
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   6
_chemical_formula_structural   CrSiSe2
_chemical_formula_sum   'Cr1 Si1 Se2'
_cell_volume   64.39
_cell_formula_units_Z   1
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
  Cr  Cr0  1  0.0  0.0  0.48  1.0
  Si  Si1  1  0.0  0.0  0.0  1.0
  Se  Se2  1  0.12  0.0  0.01  1.0
  Se  Se3  1  0.12  0.0  0.95  1.0

Cr Si Se Se
CrSiSe2 crystallizes in the monoclinic Pm space group. Cr(1) is bonded to four equivalent Cr(1), one Se(1), and one Se(2) atom to form a mixture of distorted corner and edge-sharing CrCr4Se2 octahedra. The corner-sharing octahedra are not tilted. All Cr(1)-Cr(1) bond lengths are 3.04 Å. The Cr(1)-Se(1) bond length is 3.28 Å. The Cr(1)-Se(2) bond length is 3.28 Å. Si(1) is bonded in a 2-coordinate geometry to one Se(1) and one Se(2) atom. The Si(1)-Se(1) bond length is 0.52 Å. The Si(1)-Se(2) bond length is 0.38 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 2-coordinate geometry to one Cr(1), one Si(1), and one Se(2) atom. The Se(1)-Se(2) bond length is 0.44 Å. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to one Cr(1), one Si(1), and one Se(1) atom.