data_HfCuSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.34
_cell_length_b   3.34
_cell_length_c   6.48
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   HfCuSe2
_chemical_formula_sum   'Hf1 Cu1 Se2'
_cell_volume   72.4
_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
  Hf  Hf1  1  0.0  0.0  0.24  1.0
  Cu  Cu0  1  0.0  0.0  0.0  1.0
  Se  Se2  1  0.67  0.67  0.81  1.0
  Se  Se3  1  0.67  0.67  0.68  1.0

data_HfCuSe2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.73
_cell_length_b   4.73
_cell_length_c   6.48
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   HfCuSe2
_chemical_formula_sum   'Hf2 Cu2 Se4'
_cell_volume   144.81
_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
  Hf  Hf0  2  0.0  0.0  0.24  1.0
  Cu  Cu1  2  0.0  0.0  0.0  1.0
  Se  Se2  2  0.17  0.5  0.68  1.0
  Se  Se3  2  0.17  0.5  0.81  1.0

Hf Cu Se Se
HfCuSe2 crystallizes in the monoclinic Cm space group. Hf(1) is bonded in a distorted single-bond geometry to one Cu(1) and one Se(2) atom. The Hf(1)-Cu(1) bond length is 1.56 Å. The Hf(1)-Se(2) bond length is 3.22 Å. Cu(1) is bonded in a 2-coordinate geometry to one Hf(1) and three equivalent Se(1) atoms. There is one shorter (2.00 Å) and two longer (2.79 Å) Cu(1)-Se(1) bond lengths. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 4-coordinate geometry to three equivalent Cu(1) and one Se(2) atom. The Se(1)-Se(2) bond length is 0.85 Å. In the second Se site, Se(2) is bonded in a distorted bent 150 degrees geometry to one Hf(1) and one Se(1) atom.