data_Mg2ZrZn
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   10.23
_cell_length_b   10.23
_cell_length_c   10.23
_cell_angle_alpha   17.29
_cell_angle_beta   17.29
_cell_angle_gamma   17.29
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2ZrZn
_chemical_formula_sum   'Mg2 Zr1 Zn1'
_cell_volume   82.56
_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  Mg0  1  0.0  0.0  0.77  1.0
  Mg  Mg1  1  0.0  0.0  0.45  1.0
  Zr  Zr3  1  0.0  0.0  0.11  1.0
  Zn  Zn2  1  0.0  0.0  0.0  1.0

data_Mg2ZrZn
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.33
_cell_length_b   3.08
_cell_length_c   10.23
_cell_angle_alpha   90.0
_cell_angle_beta   100.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Mg2ZrZn
_chemical_formula_sum   'Mg4 Zr2 Zn2'
_cell_volume   165.12
_cell_formula_units_Z   2
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  'x, -y, z'
  3  'x+1/2, y+1/2, z'
  4  'x+1/2, -y+1/2, 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  2  -0.0  0.0  0.55  1.0
  Mg  Mg1  2  0.0  0.0  0.23  1.0
  Zr  Zr2  2  0.0  0.0  0.89  1.0
  Zn  Zn3  2  0.0  0.0  0.0  1.0

Mg Mg Zr Zn
Mg Mg Zr Zn 0 0 o + - 0 0 + - o 0 0 + o - 0 1 o o o 0 3 o o + 1 1 o + - 1 1 + - o 1 1 + o - 1 2 o o o 2 3 o o o 
Mg2ZrZn crystallizes in the monoclinic Cm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a single-bond geometry to one Mg(2) and one Zn(1) atom. The Mg(1)-Mg(2) bond length is 3.23 Å. The Mg(1)-Zn(1) bond length is 2.35 Å. In the second Mg site, Mg(2) is bonded to one Mg(1), six equivalent Mg(2), and one Zr(1) atom to form a mixture of corner and edge-sharing MgMg7Zr hexagonal bipyramids. All Mg(2)-Mg(2) bond lengths are 3.08 Å. The Mg(2)-Zr(1) bond length is 3.50 Å. Zr(1) is bonded in a single-bond geometry to one Mg(2) and one Zn(1) atom. The Zr(1)-Zn(1) bond length is 1.15 Å. Zn(1) is bonded in a distorted single-bond geometry to one Mg(1) and one Zr(1) atom.