data_GdAlSi2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.79
_cell_length_b   4.79
_cell_length_c   4.79
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   GdAlSi2
_chemical_formula_sum   'Gd1 Al1 Si2'
_cell_volume   77.82
_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
  Gd  Gd1  1  0.39  0.39  0.39  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0
  Si  Si2  1  0.08  0.08  0.08  1.0
  Si  Si3  1  0.69  0.69  0.69  1.0

data_GdAlSi2
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.79
_cell_length_b   4.79
_cell_length_c   11.74
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   GdAlSi2
_chemical_formula_sum   'Gd3 Al3 Si6'
_cell_volume   233.46
_cell_formula_units_Z   3
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x-y, z'
  3  '-x+y, -x, z'
  4  '-y, -x, z'
  5  '-x+y, y, z'
  6  'x, x-y, z'
  7  'x+1/3, y+2/3, z+2/3'
  8  '-y+1/3, x-y+2/3, z+2/3'
  9  '-x+y+1/3, -x+2/3, z+2/3'
  10  '-y+1/3, -x+2/3, z+2/3'
  11  '-x+y+1/3, y+2/3, z+2/3'
  12  'x+1/3, x-y+2/3, z+2/3'
  13  'x+2/3, y+1/3, z+1/3'
  14  '-y+2/3, x-y+1/3, z+1/3'
  15  '-x+y+2/3, -x+1/3, z+1/3'
  16  '-y+2/3, -x+1/3, z+1/3'
  17  '-x+y+2/3, y+1/3, z+1/3'
  18  'x+2/3, x-y+1/3, z+1/3'
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
  Gd  Gd0  3  0.0  0.0  0.61  1.0
  Al  Al1  3  0.0  0.0  0.0  1.0
  Si  Si2  3  0.0  0.0  0.31  1.0
  Si  Si3  3  0.0  0.0  0.92  1.0

Gd Al Si Si
Gd Al Si Si 0 2 o o + 0 2 o + o 0 2 + o o 0 1 o o + 0 1 o + o 0 1 + o o 0 3 - o o 0 3 o - o 0 3 o o - 1 2 o o o 1 3 o - - 1 3 - o - 1 3 - - o 2 3 o - - 2 3 - o - 2 3 - - o 
GdAlSi2 crystallizes in the trigonal R3m space group. Gd(1) is bonded in a 11-coordinate geometry to three equivalent Al(1), four equivalent Si(1), and four equivalent Si(2) atoms. All Gd(1)-Al(1) bond lengths are 2.84 Å. There are three shorter (2.79 Å) and one longer (3.59 Å) Gd(1)-Si(1) bond length. There are three shorter (2.79 Å) and one longer (3.59 Å) Gd(1)-Si(2) bond length. Al(1) is bonded in a single-bond geometry to three equivalent Gd(1), one Si(1), and three equivalent Si(2) atoms. The Al(1)-Si(1) bond length is 0.97 Å. All Al(1)-Si(2) bond lengths are 2.79 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a single-bond geometry to four equivalent Gd(1) and one Al(1) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to four equivalent Gd(1) and three equivalent Al(1) atoms.