The crystal structure described by BaAl2Si2 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded in a body-centered cubic geometry to eight equivalent Si(1) atoms. Al(1) is bonded to four equivalent Si(1) atoms to form a mixture of edge and corner-sharing AlSi4 tetrahedra. Si(1) is bonded in a 8-coordinate geometry to four equivalent Ba(1) and four equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Ba(AlSi)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.137
_cell_length_b   4.137
_cell_length_c   7.393
_cell_angle_alpha   106.248
_cell_angle_beta   106.248
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   116.187
_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
  Ba  Ba0  1  0.000  0.000  0.000  1.0
  Al  Al1  1  0.750  0.250  0.500  1.0
  Al  Al2  1  0.250  0.750  0.500  1.0
  Si  Si3  1  0.359  0.359  0.717  1.0
  Si  Si4  1  0.641  0.641  0.283  1.0
[/CIF]
.
The crystal structure described by BaAl2Si2 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded in a body-centered cubic geometry to eight equivalent Si(1) atoms. Al(1) is bonded to four equivalent Si(1) atoms to form a mixture of edge and corner-sharing AlSi4 tetrahedra. Si(1) is bonded in a 8-coordinate geometry to four equivalent Ba(1) and four equivalent Al(1) atoms. is represented by the CIF card [CIF]
data_Ba(AlSi)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.137
_cell_length_b   4.137
_cell_length_c   7.393
_cell_angle_alpha   106.248
_cell_angle_beta   106.248
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   116.187
_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
  Ba  Ba0  1  0.000  0.000  0.000  1.0
  Al  Al1  1  0.750  0.250  0.500  1.0
  Al  Al2  1  0.250  0.750  0.500  1.0
  Si  Si3  1  0.359  0.359  0.717  1.0
  Si  Si4  1  0.641  0.641  0.283  1.0
[/CIF]
.