data_CaAl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.32
_cell_length_b   3.32
_cell_length_c   4.83
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   CaAl
_chemical_formula_sum   'Ca1 Al1'
_cell_volume   53.28
_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
  Ca  Ca1  1  0.66  0.66  0.42  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0

data_CaAl
_symmetry_space_group_name_H-M   Cm
_cell_length_a   4.7
_cell_length_b   4.7
_cell_length_c   4.83
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   CaAl
_chemical_formula_sum   'Ca2 Al2'
_cell_volume   106.56
_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
  Ca  Ca0  2  0.16  0.5  0.42  1.0
  Al  Al1  2  0.0  0.0  0.0  1.0

Ca Al
Ca Al 0 1 o + o 0 1 + o o 0 1 + + o 0 1 + + + 0 0 + o o 0 0 o + o 1 1 + o o 1 1 o + o 
CaAl is Tetraauricupride structured and crystallizes in the monoclinic Cm space group. Ca(1) is bonded in a 1-coordinate geometry to four equivalent Al(1) atoms. There are a spread of Ca(1)-Al(1) bond distances ranging from 2.57-3.24 Å. Al(1) is bonded in a 4-coordinate geometry to four equivalent Ca(1) atoms.