data_PdSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.44
_cell_length_b   4.44
_cell_length_c   4.44
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   PdSe2
_chemical_formula_sum   'Pd1 Se2'
_cell_volume   61.95
_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
  Pd  Pd0  1  0.0  0.0  0.0  1.0
  Se  Se1  1  0.71  0.71  0.71  1.0
  Se  Se2  1  0.57  0.57  0.57  1.0

data_PdSe2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.44
_cell_length_b   4.44
_cell_length_c   10.88
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   PdSe2
_chemical_formula_sum   'Pd3 Se6'
_cell_volume   185.86
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Pd  Pd0  3  0.0  0.0  0.0  1.0
  Se  Se1  3  0.0  0.0  0.29  1.0
  Se  Se2  3  0.0  0.0  0.43  1.0

Pd Se Se
Pd Se Se 0 1 - - - 0 1 - - o 0 1 - o - 0 1 o - - 0 2 - - o 0 2 - o - 0 2 o - - 1 2 o o o 
PdSe2 crystallizes in the trigonal R3m space group. Pd(1) is bonded in a 7-coordinate geometry to three equivalent Se(2) and four equivalent Se(1) atoms. All Pd(1)-Se(2) bond lengths are 2.77 Å. There are three shorter (2.61 Å) and one longer (3.15 Å) Pd(1)-Se(1) bond length. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 5-coordinate geometry to four equivalent Pd(1) and one Se(2) atom. The Se(1)-Se(2) bond length is 1.53 Å. In the second Se site, Se(2) is bonded in a distorted single-bond geometry to three equivalent Pd(1) and one Se(1) atom.