data_Zn2SiAs
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.59
_cell_length_b   4.59
_cell_length_c   4.59
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Zn2SiAs
_chemical_formula_sum   'Zn2 Si1 As1'
_cell_volume   68.26
_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
  Zn  Zn2  1  0.87  0.87  0.87  1.0
  Zn  Zn3  1  0.24  0.24  0.24  1.0
  Si  Si1  1  0.0  0.0  0.0  1.0
  As  As0  1  0.62  0.62  0.62  1.0

data_Zn2SiAs
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.59
_cell_length_b   4.59
_cell_length_c   11.24
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Zn2SiAs
_chemical_formula_sum   'Zn6 Si3 As3'
_cell_volume   204.78
_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
  Zn  Zn0  3  0.0  0.0  0.13  1.0
  Zn  Zn1  3  0.0  0.0  0.76  1.0
  Si  Si2  3  0.0  0.0  0.0  1.0
  As  As3  3  0.0  0.0  0.38  1.0

Zn Zn Si As
Zn2SiAs is Heusler structured and crystallizes in the trigonal R3m space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded in a distorted single-bond geometry to three equivalent Zn(2), one Si(1), and four equivalent As(1) atoms. All Zn(1)-Zn(2) bond lengths are 2.70 Å. The Zn(1)-Si(1) bond length is 1.51 Å. There is one shorter (2.74 Å) and three longer (2.83 Å) Zn(1)-As(1) bond lengths. In the second Zn site, Zn(2) is bonded in a 10-coordinate geometry to three equivalent Zn(1), four equivalent Si(1), and three equivalent As(1) atoms. There is one shorter (2.74 Å) and three longer (2.83 Å) Zn(2)-Si(1) bond lengths. All Zn(2)-As(1) bond lengths are 2.70 Å. Si(1) is bonded in a single-bond geometry to one Zn(1), four equivalent Zn(2), and three equivalent As(1) atoms. All Si(1)-As(1) bond lengths are 2.70 Å. As(1) is bonded in a 10-coordinate geometry to three equivalent Zn(2), four equivalent Zn(1), and three equivalent Si(1) atoms.