data_BaCuOs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.91
_cell_length_b   4.91
_cell_length_c   4.91
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   BaCuOs
_chemical_formula_sum   'Ba1 Cu1 Os1'
_cell_volume   83.83
_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
  Ba  Ba0  1  0.74  0.74  0.74  1.0
  Cu  Cu1  1  0.0  0.0  0.0  1.0
  Os  Os2  1  0.47  0.47  0.47  1.0

data_BaCuOs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.91
_cell_length_b   4.91
_cell_length_c   12.03
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   BaCuOs
_chemical_formula_sum   'Ba3 Cu3 Os3'
_cell_volume   251.48
_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
  Ba  Ba0  3  0.0  0.0  0.26  1.0
  Cu  Cu1  3  0.0  0.0  1.0  1.0
  Os  Os2  3  0.0  0.0  0.53  1.0

Ba Cu Os
BaOsCu is half-Heusler structured and crystallizes in the trigonal R3m space group. Ba(1) is bonded in a body-centered cubic geometry to four equivalent Os(1) and four equivalent Cu(1) atoms. There are three shorter (2.96 Å) and one longer (3.17 Å) Ba(1)-Os(1) bond length. There are three shorter (2.96 Å) and one longer (3.17 Å) Ba(1)-Cu(1) bond length. Os(1) is bonded to four equivalent Ba(1) and three equivalent Cu(1) atoms to form distorted OsBa4Cu3 tetrahedra that share corners with four equivalent Cu(1)Ba4Os3 tetrahedra, corners with six equivalent Os(1)Ba4Cu3 tetrahedra, edges with six equivalent Os(1)Ba4Cu3 tetrahedra, and edges with six equivalent Cu(1)Ba4Os3 tetrahedra. All Os(1)-Cu(1) bond lengths are 3.30 Å. Cu(1) is bonded to four equivalent Ba(1) and three equivalent Os(1) atoms to form distorted CuBa4Os3 tetrahedra that share corners with four equivalent Os(1)Ba4Cu3 tetrahedra, corners with six equivalent Cu(1)Ba4Os3 tetrahedra, edges with six equivalent Os(1)Ba4Cu3 tetrahedra, and edges with six equivalent Cu(1)Ba4Os3 tetrahedra.