data_TaBeAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.03
_cell_length_b   4.03
_cell_length_c   4.03
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   TaBeAs
_chemical_formula_sum   'Ta1 Be1 As1'
_cell_volume   46.23
_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
  Ta  Ta2  1  0.27  0.27  0.27  1.0
  Be  Be1  1  0.0  0.0  0.0  1.0
  As  As0  1  0.42  0.42  0.42  1.0

data_TaBeAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.03
_cell_length_b   4.03
_cell_length_c   9.87
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   TaBeAs
_chemical_formula_sum   'Ta3 Be3 As3'
_cell_volume   138.68
_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
  Ta  Ta0  3  0.0  0.0  0.73  1.0
  Be  Be1  3  0.0  0.0  0.0  1.0
  As  As2  3  0.0  0.0  0.58  1.0

Ta Be As
Ta Be As 0 2 o o o 0 1 + o o 0 1 o + o 0 1 o o + 0 1 o o o 1 2 - o o 1 2 o - o 1 2 o o - 
BeTaAs is half-Heusler structured and crystallizes in the trigonal R3m space group. Be(1) is bonded in a 7-coordinate geometry to four equivalent Ta(1) and three equivalent As(1) atoms. There are three shorter (2.40 Å) and one longer (2.69 Å) Be(1)-Ta(1) bond length. All Be(1)-As(1) bond lengths are 2.49 Å. Ta(1) is bonded in a single-bond geometry to four equivalent Be(1) and one As(1) atom. The Ta(1)-As(1) bond length is 1.49 Å. As(1) is bonded in a single-bond geometry to three equivalent Be(1) and one Ta(1) atom.