data_FePSe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.15
_cell_length_b   3.15
_cell_length_c   7.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   FePSe2
_chemical_formula_sum   'Fe1 P1 Se2'
_cell_volume   71.12
_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
  Fe  Fe0  1  0.58  0.58  0.1  1.0
  P  P1  1  0.0  0.0  0.83  1.0
  Se  Se2  1  0.58  0.58  0.51  1.0
  Se  Se3  1  0.0  0.0  0.46  1.0

data_FePSe2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.46
_cell_length_b   4.46
_cell_length_c   7.16
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   FePSe2
_chemical_formula_sum   'Fe2 P2 Se4'
_cell_volume   142.24
_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
  Fe  Fe0  2  0.08  0.5  0.1  1.0
  P  P1  2  0.0  0.0  0.83  1.0
  Se  Se2  2  0.0  0.0  0.46  1.0
  Se  Se3  2  0.08  0.5  0.51  1.0

Fe P Se Se
Fe P Se Se 0 1 o o - 0 1 o + - 0 1 + o - 0 1 + + - 0 3 o + o 0 3 + o o 0 3 + + o 0 0 + o o 0 0 o + o 0 2 o o o 1 2 - - o 1 2 - o o 1 2 o - o 1 2 o o o 1 1 + o o 1 1 o + o 1 3 o o o 2 3 o + o 2 3 + o o 2 3 + + o 
FePSe2 crystallizes in the monoclinic Cm space group. Fe(1) is bonded in a 5-coordinate geometry to three equivalent P(1), one Se(1), and one Se(2) atom. There is one shorter (2.74 Å) and two longer (3.00 Å) Fe(1)-P(1) bond lengths. The Fe(1)-Se(1) bond length is 2.95 Å. The Fe(1)-Se(2) bond length is 3.16 Å. P(1) is bonded in a 5-coordinate geometry to three equivalent Fe(1), one Se(1), and one Se(2) atom. The P(1)-Se(1) bond length is 2.92 Å. The P(1)-Se(2) bond length is 2.64 Å. There are two inequivalent Se sites. In the first Se site, Se(1) is bonded in a 6-coordinate geometry to one Fe(1), one P(1), and four equivalent Se(2) atoms. There are a spread of Se(1)-Se(2) bond distances ranging from 1.93-2.60 Å. In the second Se site, Se(2) is bonded in a 6-coordinate geometry to one Fe(1), one P(1), and four equivalent Se(1) atoms.