data_Sc2FeSe
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.27
_cell_length_b   3.27
_cell_length_c   6.51
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sc2FeSe
_chemical_formula_sum   'Sc2 Fe1 Se1'
_cell_volume   69.43
_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
  Sc  Sc1  1  0.63  0.63  0.51  1.0
  Sc  Sc2  1  0.63  0.63  0.0  1.0
  Fe  Fe0  1  0.0  0.0  0.0  1.0
  Se  Se3  1  0.0  0.0  0.25  1.0

data_Sc2FeSe
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.62
_cell_length_b   4.62
_cell_length_c   6.51
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Sc2FeSe
_chemical_formula_sum   'Sc4 Fe2 Se2'
_cell_volume   138.87
_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
  Sc  Sc0  2  0.13  0.5  0.0  1.0
  Sc  Sc1  2  0.13  0.5  0.51  1.0
  Fe  Fe2  2  0.0  0.0  0.0  1.0
  Se  Se3  2  0.0  0.0  0.25  1.0

Sc Sc Fe Se
Sc Sc Fe Se 0 3 o + o 0 3 + o o 0 3 + + o 0 0 + o o 0 0 o + o 0 1 o o o 0 1 o o + 1 2 + + o 2 3 o o o 
Sc2FeSe crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Sc2FeSe clusters. There are two inequivalent Sc sites. In the first Sc site, Sc(1) is bonded in a 1-coordinate geometry to one Se(1) atom. The Sc(1)-Se(1) bond length is 2.36 Å. In the second Sc site, Sc(2) is bonded in a 1-coordinate geometry to one Fe(1) atom. The Sc(2)-Fe(1) bond length is 1.70 Å. Fe(1) is bonded in a 2-coordinate geometry to one Sc(2) and one Se(1) atom. The Fe(1)-Se(1) bond length is 1.66 Å. Se(1) is bonded in a 2-coordinate geometry to one Sc(1) and one Fe(1) atom.