data_KCa2Al
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.78
_cell_length_b   3.78
_cell_length_c   10.94
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   KCa2Al
_chemical_formula_sum   'K1 Ca2 Al1'
_cell_volume   156.21
_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
  K  K3  1  0.0  0.0  0.47  1.0
  Ca  Ca1  1  0.89  0.89  0.83  1.0
  Ca  Ca2  1  0.89  0.89  0.12  1.0
  Al  Al0  1  0.0  0.0  0.0  1.0

data_KCa2Al
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.34
_cell_length_b   5.34
_cell_length_c   10.94
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   KCa2Al
_chemical_formula_sum   'K2 Ca4 Al2'
_cell_volume   312.43
_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
  K  K0  2  0.0  0.0  0.47  1.0
  Ca  Ca1  2  0.39  0.5  0.12  1.0
  Ca  Ca2  2  0.39  0.5  0.83  1.0
  Al  Al3  2  0.0  0.0  0.0  1.0

K Ca Ca Al
KCa2Al crystallizes in the monoclinic Cm space group. K(1) is bonded to four equivalent K(1), one Ca(1), and one Ca(2) atom to form a mixture of corner and edge-sharing KK4Ca2 octahedra. The corner-sharing octahedra are not tilted. All K(1)-K(1) bond lengths are 3.78 Å. The K(1)-Ca(1) bond length is 3.91 Å. The K(1)-Ca(2) bond length is 3.91 Å. There are two inequivalent Ca sites. In the first Ca site, Ca(1) is bonded in a single-bond geometry to one K(1) and one Al(1) atom. The Ca(1)-Al(1) bond length is 2.00 Å. In the second Ca site, Ca(2) is bonded in a single-bond geometry to one K(1) and one Al(1) atom. The Ca(2)-Al(1) bond length is 1.44 Å. Al(1) is bonded in a distorted bent 150 degrees geometry to one Ca(1) and one Ca(2) atom.