data_NaAlCo
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.41
_cell_length_b   4.41
_cell_length_c   4.41
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   NaAlCo
_chemical_formula_sum   'Na1 Al1 Co1'
_cell_volume   60.67
_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
  Na  Na2  1  0.0  0.0  0.0  1.0
  Al  Al0  1  0.68  0.68  0.68  1.0
  Co  Co1  1  0.56  0.56  0.56  1.0

data_NaAlCo
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.41
_cell_length_b   4.41
_cell_length_c   10.8
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   NaAlCo
_chemical_formula_sum   'Na3 Al3 Co3'
_cell_volume   182.02
_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
  Na  Na0  3  0.0  0.0  0.0  1.0
  Al  Al1  3  0.0  0.0  0.32  1.0
  Co  Co2  3  0.0  0.0  0.44  1.0

Na Al Co
Na Al Co 0 2 - - o 0 2 - o - 0 2 o - - 0 1 - - o 0 1 - o - 0 1 o - - 1 2 o o o 
NaCoAl is half-Heusler structured and crystallizes in the trigonal R3m space group. Na(1) is bonded in a 10-coordinate geometry to six equivalent Co(1) and four equivalent Al(1) atoms. There are three shorter (2.80 Å) and three longer (3.53 Å) Na(1)-Co(1) bond lengths. There are three shorter (2.55 Å) and one longer (3.48 Å) Na(1)-Al(1) bond length. Co(1) is bonded in a single-bond geometry to six equivalent Na(1) and one Al(1) atom. The Co(1)-Al(1) bond length is 1.28 Å. Al(1) is bonded in a distorted single-bond geometry to four equivalent Na(1) and one Co(1) atom.