data_Cs2SrAl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.82
_cell_length_b   6.82
_cell_length_c   6.82
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Cs2SrAl
_chemical_formula_sum   'Cs2 Sr1 Al1'
_cell_volume   224.38
_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
  Cs  Cs1  1  0.41  0.41  0.41  1.0
  Cs  Cs2  1  0.23  0.23  0.23  1.0
  Sr  Sr3  1  0.82  0.82  0.82  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0

data_Cs2SrAl
_symmetry_space_group_name_H-M   R3m
_cell_length_a   6.82
_cell_length_b   6.82
_cell_length_c   16.71
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Cs2SrAl
_chemical_formula_sum   'Cs6 Sr3 Al3'
_cell_volume   673.14
_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
  Cs  Cs0  3  0.0  0.0  0.59  1.0
  Cs  Cs1  3  0.0  0.0  0.77  1.0
  Sr  Sr2  3  0.0  0.0  0.18  1.0
  Al  Al3  3  0.0  0.0  0.0  1.0

Cs Cs Sr Al
Cs Cs Sr Al 0 1 o o o 2 3 + + + 
Cs2SrAl crystallizes in the trigonal R3m space group. There are two inequivalent Cs sites. In the first Cs site, Cs(1) is bonded in a 7-coordinate geometry to one Cs(2), three equivalent Sr(1), and three equivalent Al(1) atoms. The Cs(1)-Cs(2) bond length is 2.96 Å. All Cs(1)-Sr(1) bond lengths are 4.15 Å. All Cs(1)-Al(1) bond lengths are 4.15 Å. In the second Cs site, Cs(2) is bonded in a 8-coordinate geometry to one Cs(1), three equivalent Sr(1), and four equivalent Al(1) atoms. All Cs(2)-Sr(1) bond lengths are 4.15 Å. There is one shorter (3.92 Å) and three longer (4.27 Å) Cs(2)-Al(1) bond lengths. Sr(1) is bonded in a single-bond geometry to three equivalent Cs(1), three equivalent Cs(2), and one Al(1) atom. The Sr(1)-Al(1) bond length is 2.96 Å. Al(1) is bonded in a 1-coordinate geometry to three equivalent Cs(1), four equivalent Cs(2), and one Sr(1) atom.