The compound described by Be3Si is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to four equivalent Be(1), four equivalent Be(2), and four equivalent Si(1) atoms to form BeBe8Si4 cuboctahedra that share corners with twelve equivalent Be(1)Be8Si4 cuboctahedra, edges with eight equivalent Be(1)Be8Si4 cuboctahedra, edges with eight equivalent Be(2)Be8Si4 cuboctahedra, edges with eight equivalent Si(1)Be12 cuboctahedra, faces with four equivalent Be(2)Be8Si4 cuboctahedra, faces with four equivalent Si(1)Be12 cuboctahedra, and faces with ten equivalent Be(1)Be8Si4 cuboctahedra. In the second Be site, Be(2) is bonded to eight equivalent Be(1) and four equivalent Si(1) atoms to form BeBe8Si4 cuboctahedra that share corners with four equivalent Be(2)Be8Si4 cuboctahedra, corners with eight equivalent Si(1)Be12 cuboctahedra, edges with eight equivalent Be(2)Be8Si4 cuboctahedra, edges with sixteen equivalent Be(1)Be8Si4 cuboctahedra, faces with four equivalent Be(2)Be8Si4 cuboctahedra, faces with six equivalent Si(1)Be12 cuboctahedra, and faces with eight equivalent Be(1)Be8Si4 cuboctahedra. Si(1) is bonded to four equivalent Be(2) and eight equivalent Be(1) atoms to form SiBe12 cuboctahedra that share corners with four equivalent Si(1)Be12 cuboctahedra, corners with eight equivalent Be(2)Be8Si4 cuboctahedra, edges with eight equivalent Si(1)Be12 cuboctahedra, edges with sixteen equivalent Be(1)Be8Si4 cuboctahedra, faces with four equivalent Si(1)Be12 cuboctahedra, faces with six equivalent Be(2)Be8Si4 cuboctahedra, and faces with eight equivalent Be(1)Be8Si4 cuboctahedra. is represented by the CIF card [CIF]
data_Be3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.188
_cell_length_b   4.188
_cell_length_c   4.188
_cell_angle_alpha   131.930
_cell_angle_beta   131.930
_cell_angle_gamma   70.339
_symmetry_Int_Tables_number   1
_cell_volume   39.831
_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  0.750  0.250  0.500  1.0
  Be  Be1  1  0.250  0.750  0.500  1.0
  Be  Be2  1  0.500  0.500  0.000  1.0
  Si  Si3  1  0.000  0.000  0.000  1.0
[/CIF]
.
The compound described by Be3Si is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to four equivalent Be(1), four equivalent Be(2), and four equivalent Si(1) atoms to form BeBe8Si4 cuboctahedra that share corners with twelve equivalent Be(1)Be8Si4 cuboctahedra, edges with eight equivalent Be(1)Be8Si4 cuboctahedra, edges with eight equivalent Be(2)Be8Si4 cuboctahedra, edges with eight equivalent Si(1)Be12 cuboctahedra, faces with four equivalent Be(2)Be8Si4 cuboctahedra, faces with four equivalent Si(1)Be12 cuboctahedra, and faces with ten equivalent Be(1)Be8Si4 cuboctahedra. In the second Be site, Be(2) is bonded to eight equivalent Be(1) and four equivalent Si(1) atoms to form BeBe8Si4 cuboctahedra that share corners with four equivalent Be(2)Be8Si4 cuboctahedra, corners with eight equivalent Si(1)Be12 cuboctahedra, edges with eight equivalent Be(2)Be8Si4 cuboctahedra, edges with sixteen equivalent Be(1)Be8Si4 cuboctahedra, faces with four equivalent Be(2)Be8Si4 cuboctahedra, faces with six equivalent Si(1)Be12 cuboctahedra, and faces with eight equivalent Be(1)Be8Si4 cuboctahedra. Si(1) is bonded to four equivalent Be(2) and eight equivalent Be(1) atoms to form SiBe12 cuboctahedra that share corners with four equivalent Si(1)Be12 cuboctahedra, corners with eight equivalent Be(2)Be8Si4 cuboctahedra, edges with eight equivalent Si(1)Be12 cuboctahedra, edges with sixteen equivalent Be(1)Be8Si4 cuboctahedra, faces with four equivalent Si(1)Be12 cuboctahedra, faces with six equivalent Be(2)Be8Si4 cuboctahedra, and faces with eight equivalent Be(1)Be8Si4 cuboctahedra. is represented by the CIF card [CIF]
data_Be3Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.188
_cell_length_b   4.188
_cell_length_c   4.188
_cell_angle_alpha   131.930
_cell_angle_beta   131.930
_cell_angle_gamma   70.339
_symmetry_Int_Tables_number   1
_cell_volume   39.831
_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  0.750  0.250  0.500  1.0
  Be  Be1  1  0.250  0.750  0.500  1.0
  Be  Be2  1  0.500  0.500  0.000  1.0
  Si  Si3  1  0.000  0.000  0.000  1.0
[/CIF]
.