data_Be2Si2Sn
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.9
_cell_length_b   5.9
_cell_length_c   5.9
_cell_angle_alpha   143.07
_cell_angle_beta   143.07
_cell_angle_gamma   53.22
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Be2Si2Sn
_chemical_formula_sum   'Be2 Si2 Sn1'
_cell_volume   73.65
_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  0.43  1.0
  Be  Be1  1  0.0  0.0  0.12  1.0
  Si  Si2  1  0.0  0.87  0.64  1.0
  Si  Si3  1  0.87  0.0  0.64  1.0
  Sn  Sn4  1  0.0  0.0  0.0  1.0

data_Be2Si2Sn
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.28
_cell_length_b   5.28
_cell_length_c   5.9
_cell_angle_alpha   90.0
_cell_angle_beta   116.61
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Be2Si2Sn
_chemical_formula_sum   'Be4 Si4 Sn2'
_cell_volume   147.29
_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  0.57  1.0
  Be  Be1  2  0.0  0.0  0.88  1.0
  Si  Si2  4  0.43  0.43  0.23  1.0
  Sn  Sn3  2  0.0  0.0  0.0  1.0

Be Be Si Si Sn
Be Be Si Si Sn 0 3 - o o 0 2 o - o 0 1 o o o 1 4 o o o 2 3 - + o 
Be2SnSi2 is Indium-like structured and crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two Be2SnSi2 clusters. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 3-coordinate geometry to one Be(2) and two equivalent Si(1) atoms. The Be(1)-Be(2) bond length is 1.83 Å. Both Be(1)-Si(1) bond lengths are 1.90 Å. In the second Be site, Be(2) is bonded in a single-bond geometry to one Be(1) and one Sn(1) atom. The Be(2)-Sn(1) bond length is 0.70 Å. Sn(1) is bonded in a single-bond geometry to one Be(2) atom. Si(1) is bonded in a distorted single-bond geometry to one Be(1) and one Si(1) atom. The Si(1)-Si(1) bond length is 0.70 Å.