data_SnGe2As
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.93
_cell_length_b   4.93
_cell_length_c   4.93
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SnGe2As
_chemical_formula_sum   'Sn1 Ge2 As1'
_cell_volume   84.95
_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
  Sn  Sn3  1  0.74  0.74  0.74  1.0
  Ge  Ge1  1  0.0  0.0  0.0  1.0
  Ge  Ge2  1  0.23  0.23  0.23  1.0
  As  As0  1  0.49  0.49  0.49  1.0

data_SnGe2As
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.93
_cell_length_b   4.93
_cell_length_c   12.09
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SnGe2As
_chemical_formula_sum   'Sn3 Ge6 As3'
_cell_volume   254.85
_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
  Sn  Sn0  3  0.0  0.0  0.26  1.0
  Ge  Ge1  3  0.0  0.0  0.0  1.0
  Ge  Ge2  3  0.0  0.0  0.77  1.0
  As  As3  3  0.0  0.0  0.51  1.0

Sn Ge Ge As
SnGe2As crystallizes in the trigonal R3m space group. Sn(1) is bonded in a body-centered cubic geometry to four equivalent Ge(1) and four equivalent As(1) atoms. There are three shorter (3.00 Å) and one longer (3.09 Å) Sn(1)-Ge(1) bond length. There are three shorter (3.00 Å) and one longer (3.09 Å) Sn(1)-As(1) bond length. There are two inequivalent Ge sites. In the first Ge site, Ge(1) is bonded in a distorted body-centered cubic geometry to four equivalent Sn(1) and four equivalent Ge(2) atoms. There is one shorter (2.82 Å) and three longer (3.09 Å) Ge(1)-Ge(2) bond lengths. In the second Ge site, Ge(2) is bonded in a 8-coordinate geometry to four equivalent Ge(1) and four equivalent As(1) atoms. There are three shorter (3.00 Å) and one longer (3.09 Å) Ge(2)-As(1) bond length. As(1) is bonded in a body-centered cubic geometry to four equivalent Sn(1) and four equivalent Ge(2) atoms.