data_Be(FeSi)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.98
_cell_length_b   5.98
_cell_length_c   5.98
_cell_angle_alpha   147.85
_cell_angle_beta   147.85
_cell_angle_gamma   46.11
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be(FeSi)2
_chemical_formula_sum   'Be1 Fe2 Si2'
_cell_volume   60.31
_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
  Be  Be0  1  0.0  0.0  0.0  1.0
  Fe  Fe1  1  0.0  0.0  0.66  1.0
  Fe  Fe2  1  0.0  0.0  0.34  1.0
  Si  Si3  1  0.0  0.66  0.75  1.0
  Si  Si4  1  0.66  0.0  0.75  1.0

data_Be(FeSi)2
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.68
_cell_length_b   4.68
_cell_length_c   5.98
_cell_angle_alpha   90.0
_cell_angle_beta   113.05
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Be(FeSi)2
_chemical_formula_sum   'Be2 Fe4 Si4'
_cell_volume   120.61
_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
  Be  Be0  2  0.0  0.0  0.0  1.0
  Fe  Fe1  2  0.16  0.5  0.66  1.0
  Fe  Fe2  2  0.34  0.0  0.34  1.0
  Si  Si3  4  0.42  0.33  0.1  1.0

Be Fe Fe Si Si
Be Fe Fe Si Si 0 4 - o - 0 3 o - - 0 1 o o - 0 2 o o o 1 2 o o o 2 3 o o o 2 3 o - - 2 4 - o - 2 4 o o o 
Be(FeSi)2 crystallizes in the monoclinic Cm space group. Be(1) is bonded in a distorted L-shaped geometry to one Fe(1), one Fe(2), and two equivalent Si(1) atoms. The Be(1)-Fe(1) bond length is 2.02 Å. The Be(1)-Fe(2) bond length is 2.03 Å. Both Be(1)-Si(1) bond lengths are 1.13 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a distorted linear geometry to one Be(1) and one Fe(2) atom. The Fe(1)-Fe(2) bond length is 1.93 Å. In the second Fe site, Fe(2) is bonded in a 6-coordinate geometry to one Be(1), one Fe(1), and four equivalent Si(1) atoms. There are two shorter (2.09 Å) and two longer (2.26 Å) Fe(2)-Si(1) bond lengths. Si(1) is bonded in a single-bond geometry to one Be(1) and two equivalent Fe(2) atoms.