data_Sr2MgAu
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.44
_cell_length_b   5.44
_cell_length_c   5.44
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Sr2MgAu
_chemical_formula_sum   'Sr2 Mg1 Au1'
_cell_volume   113.86
_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  Sr2  1  0.77  0.77  0.77  1.0
  Sr  Sr3  1  0.85  0.85  0.85  1.0
  Mg  Mg1  1  0.0  0.0  0.0  1.0
  Au  Au0  1  0.92  0.92  0.92  1.0

data_Sr2MgAu
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.44
_cell_length_b   5.44
_cell_length_c   13.33
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   Sr2MgAu
_chemical_formula_sum   'Sr6 Mg3 Au3'
_cell_volume   341.59
_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  0.15  1.0
  Sr  Sr1  3  0.0  0.0  0.23  1.0
  Mg  Mg2  3  0.0  0.0  0.0  1.0
  Au  Au3  3  0.0  0.0  0.08  1.0

Sr Sr Mg Au
Sr Sr Mg Au 0 1 o o o 1 3 o o o 2 3 - - - 
Sr2MgAu crystallizes in the trigonal R3m space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded to one Sr(2) and three equivalent Mg(1) atoms to form distorted corner-sharing SrSrMg3 tetrahedra. The Sr(1)-Sr(2) bond length is 1.02 Å. All Sr(1)-Mg(1) bond lengths are 3.43 Å. In the second Sr site, Sr(2) is bonded in a distorted single-bond geometry to one Sr(1) and one Au(1) atom. The Sr(2)-Au(1) bond length is 1.02 Å. Mg(1) is bonded in a single-bond geometry to three equivalent Sr(1) and one Au(1) atom. The Mg(1)-Au(1) bond length is 1.02 Å. Au(1) is bonded in a linear geometry to one Sr(2) and one Mg(1) atom.