data_SrMgPb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.31
_cell_length_b   5.31
_cell_length_c   5.31
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   SrMgPb
_chemical_formula_sum   'Sr1 Mg1 Pb1'
_cell_volume   105.96
_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  0.76  0.76  0.76  1.0
  Mg  Mg0  1  0.0  0.0  0.0  1.0
  Pb  Pb1  1  0.63  0.63  0.63  1.0

data_SrMgPb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   5.31
_cell_length_b   5.31
_cell_length_c   13.01
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   SrMgPb
_chemical_formula_sum   'Sr3 Mg3 Pb3'
_cell_volume   317.87
_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  0.24  1.0
  Mg  Mg1  3  0.0  0.0  -0.0  1.0
  Pb  Pb2  3  0.0  0.0  0.37  1.0

Sr Mg Pb
SrMgPb crystallizes in the trigonal R3m space group. Sr(1) is bonded in a single-bond geometry to four equivalent Mg(1) and one Pb(1) atom. There is one shorter (3.18 Å) and three longer (3.28 Å) Sr(1)-Mg(1) bond lengths. The Sr(1)-Pb(1) bond length is 1.59 Å. Mg(1) is bonded to four equivalent Sr(1) and three equivalent Pb(1) atoms to form a mixture of distorted corner and edge-sharing MgSr4Pb3 hexagonal pyramids. All Mg(1)-Pb(1) bond lengths are 3.10 Å. Pb(1) is bonded in a single-bond geometry to one Sr(1) and three equivalent Mg(1) atoms.