data_MgBe4Pb
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.9
_cell_length_b   4.9
_cell_length_c   4.9
_cell_angle_alpha   60.0
_cell_angle_beta   60.0
_cell_angle_gamma   60.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgBe4Pb
_chemical_formula_sum   'Mg1 Be4 Pb1'
_cell_volume   83.18
_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
  Mg  Mg4  1  0.0  0.0  0.0  1.0
  Be  Be0  1  0.55  0.55  0.38  1.0
  Be  Be1  1  0.55  0.38  0.55  1.0
  Be  Be2  1  0.38  0.55  0.55  1.0
  Be  Be3  1  0.38  0.38  0.38  1.0
  Pb  Pb5  1  0.73  0.73  0.73  1.0

data_MgBe4Pb
_symmetry_space_group_name_H-M   R3m
_cell_length_a   4.9
_cell_length_b   4.9
_cell_length_c   12.0
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   120.0
_symmetry_Int_Tables_number   160
_chemical_formula_structural   MgBe4Pb
_chemical_formula_sum   'Mg3 Be12 Pb3'
_cell_volume   249.53
_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
  Mg  Mg0  3  0.0  0.0  0.0  1.0
  Be  Be1  9  0.12  0.06  0.51  1.0
  Be  Be2  3  0.0  0.0  0.62  1.0
  Pb  Pb3  3  0.0  0.0  0.27  1.0

Mg Be Be Be Be Pb
MgBe4Pb crystallizes in the trigonal R3m space group. Mg(1) is bonded in a 7-coordinate geometry to three equivalent Be(2) and four equivalent Pb(1) atoms. All Mg(1)-Be(2) bond lengths are 2.88 Å. There are three shorter (2.94 Å) and one longer (3.21 Å) Mg(1)-Pb(1) bond length. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded in a 2-coordinate geometry to one Be(2), two equivalent Be(1), and two equivalent Pb(1) atoms. The Be(1)-Be(2) bond length is 1.48 Å. Both Be(1)-Be(1) bond lengths are 0.86 Å. There is one shorter (2.60 Å) and one longer (2.91 Å) Be(1)-Pb(1) bond length. In the second Be site, Be(2) is bonded in a 9-coordinate geometry to three equivalent Mg(1), three equivalent Be(1), and three equivalent Pb(1) atoms. All Be(2)-Pb(1) bond lengths are 2.84 Å. Pb(1) is bonded in a 13-coordinate geometry to four equivalent Mg(1), three equivalent Be(2), and six equivalent Be(1) atoms.