data_SrMg2Au
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.24
_cell_length_b   5.24
_cell_length_c   5.24
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrMg2Au
_chemical_formula_sum   'Sr1 Mg2 Au1'
_cell_volume   101.99
_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
  Sr  Sr3  1  0.71  0.71  0.71  1.0
  Mg  Mg1  1  0.85  0.85  0.85  1.0
  Mg  Mg2  1  0.0  0.0  0.0  1.0
  Au  Au0  1  0.56  0.56  0.56  1.0

data_SrMg2Au
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.24
_cell_length_b   5.24
_cell_length_c   12.85
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrMg2Au
_chemical_formula_sum   'Sr3 Mg6 Au3'
_cell_volume   305.98
_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
  Sr  Sr0  3  0.0  0.0  0.29  1.0
  Mg  Mg1  3  0.0  0.0  -0.0  1.0
  Mg  Mg2  3  0.0  0.0  0.15  1.0
  Au  Au3  3  0.0  0.0  0.44  1.0

Sr Mg Mg Au
Sr Mg Mg Au 0 3 o o o 0 1 o o o 1 2 + + + 
SrMg2Au crystallizes in the trigonal R3m space group. Sr(1) is bonded in a distorted linear geometry to one Mg(1), three equivalent Mg(2), and one Au(1) atom. The Sr(1)-Mg(1) bond length is 1.87 Å. All Sr(1)-Mg(2) bond lengths are 3.07 Å. The Sr(1)-Au(1) bond length is 1.87 Å. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one Sr(1), one Mg(2), and three equivalent Au(1) atoms to form distorted corner-sharing MgSrMgAu3 trigonal bipyramids. The Mg(1)-Mg(2) bond length is 1.87 Å. All Mg(1)-Au(1) bond lengths are 3.07 Å. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to three equivalent Sr(1) and one Mg(1) atom. Au(1) is bonded in a distorted single-bond geometry to one Sr(1) and three equivalent Mg(1) atoms.