data_SrFeSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.6
_cell_length_b   4.6
_cell_length_c   4.6
_cell_angle_alpha   120.79
_cell_angle_beta   120.79
_cell_angle_gamma   88.64
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrFeSi2
_chemical_formula_sum   'Sr1 Fe1 Si2'
_cell_volume   68.15
_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
  Sr  Sr3  1  0.0  0.0  0.29  1.0
  Fe  Fe0  1  0.0  0.0  0.0  1.0
  Si  Si1  1  0.27  0.0  0.65  1.0
  Si  Si2  1  0.0  0.27  0.65  1.0

data_SrFeSi2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   6.43
_cell_length_b   6.43
_cell_length_c   4.6
_cell_angle_alpha   90.0
_cell_angle_beta   134.32
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   SrFeSi2
_chemical_formula_sum   'Sr2 Fe2 Si4'
_cell_volume   136.3
_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
  Sr  Sr0  2  0.21  0.5  0.71  1.0
  Fe  Fe1  2  0.0  0.0  0.0  1.0
  Si  Si2  4  0.49  0.14  0.63  1.0

Sr Fe Si Si
Sr Fe Si Si 0 3 o o o 0 1 o o o 0 2 o o o 2 3 o o o 
SrFeSi2 is Copper structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two SrFeSi2 clusters. Sr(1) is bonded in a 3-coordinate geometry to one Fe(1) and two equivalent Si(1) atoms. The Sr(1)-Fe(1) bond length is 1.35 Å. Both Sr(1)-Si(1) bond lengths are 1.46 Å. Fe(1) is bonded in a single-bond geometry to one Sr(1) atom. Si(1) is bonded in a single-bond geometry to one Sr(1) atom.