data_MgBe2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.75
_cell_length_b   4.75
_cell_length_c   4.75
_cell_angle_alpha   125.61
_cell_angle_beta   125.61
_cell_angle_gamma   80.53
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgBe2
_chemical_formula_sum   'Mg2 Be4'
_cell_volume   68.33
_cell_formula_units_Z   2
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  0.81  1.0
  Mg  Mg5  1  0.0  0.0  0.44  1.0
  Be  Be0  1  0.45  0.72  0.0  1.0
  Be  Be1  1  0.45  0.28  0.62  1.0
  Be  Be2  1  0.72  0.89  0.0  1.0
  Be  Be3  1  0.72  0.45  0.62  1.0

data_MgBe2
_symmetry_space_group_name_H-M   P1
_cell_length_a   4.34
_cell_length_b   4.34
_cell_length_c   4.75
_cell_angle_alpha   117.2
_cell_angle_beta   117.2
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgBe2
_chemical_formula_sum   'Mg2 Be4'
_cell_volume   68.33
_cell_formula_units_Z   2
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  Mg0  1  0.44  0.44  0.44  1.0
  Mg  Mg1  1  0.81  0.81  0.81  1.0
  Be  Be2  1  0.11  0.28  0.4  1.0
  Be  Be3  1  0.17  0.91  0.45  1.0
  Be  Be4  1  0.28  0.55  0.83  1.0
  Be  Be5  1  0.34  0.17  0.89  1.0

Mg Mg Be Be Be Be
MgBe2 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 9-coordinate geometry to one Mg(2), one Be(3), two equivalent Be(1), two equivalent Be(2), and three equivalent Be(4) atoms. The Mg(1)-Mg(2) bond length is 1.78 Å. The Mg(1)-Be(3) bond length is 2.26 Å. There is one shorter (2.34 Å) and one longer (2.62 Å) Mg(1)-Be(1) bond length. There is one shorter (2.56 Å) and one longer (2.62 Å) Mg(1)-Be(2) bond length. There are a spread of Mg(1)-Be(4) bond distances ranging from 2.53-2.92 Å. In the second Mg site, Mg(2) is bonded in a 1-coordinate geometry to one Mg(1), one Be(1), one Be(2), one Be(3), and one Be(4) atom. The Mg(2)-Be(1) bond length is 2.11 Å. The Mg(2)-Be(2) bond length is 2.14 Å. The Mg(2)-Be(3) bond length is 1.45 Å. The Mg(2)-Be(4) bond length is 2.34 Å. There are four inequivalent Be sites. In the first Be site, Be(1) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), one Be(2), and one Be(3) atom. The Be(1)-Be(2) bond length is 1.77 Å. The Be(1)-Be(3) bond length is 1.59 Å. In the second Be site, Be(2) is bonded in a 5-coordinate geometry to one Mg(2), two equivalent Mg(1), one Be(1), and one Be(4) atom. The Be(2)-Be(4) bond length is 1.59 Å. In the third Be site, Be(3) is bonded in a distorted single-bond geometry to one Mg(1), one Mg(2), one Be(1), and one Be(4) atom. The Be(3)-Be(4) bond length is 1.77 Å. In the fourth Be site, Be(4) is bonded in a 4-coordinate geometry to one Mg(2), three equivalent Mg(1), one Be(2), and one Be(3) atom.