data_Y3Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.68
_cell_length_b   3.68
_cell_length_c   8.91
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Y3Mg
_chemical_formula_sum   'Y3 Mg1'
_cell_volume   120.95
_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
  Y  Y1  1  0.84  0.84  1.0  1.0
  Y  Y2  1  0.0  0.0  0.45  1.0
  Y  Y3  1  0.84  0.84  0.91  1.0
  Mg  Mg0  1  0.0  0.0  0.0  1.0

data_Y3Mg
_symmetry_space_group_name_H-M   Cm
_cell_length_a   5.21
_cell_length_b   5.21
_cell_length_c   8.91
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   8
_chemical_formula_structural   Y3Mg
_chemical_formula_sum   'Y6 Mg2'
_cell_volume   241.9
_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
  Y  Y0  2  0.0  0.0  0.45  1.0
  Y  Y1  2  0.34  0.5  0.91  1.0
  Y  Y2  2  0.34  0.5  1.0  1.0
  Mg  Mg3  2  0.0  0.0  0.0  1.0

Y Y Y Mg
Y Y Y Mg 0 2 o o o 0 3 + + + 0 1 + + + 1 2 - - o 1 1 + o o 1 1 o + o 1 3 o o o 
MgY3 crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a distorted single-bond geometry to one Y(1) and one Y(2) atom. The Mg(1)-Y(1) bond length is 0.82 Å. The Mg(1)-Y(2) bond length is 4.05 Å. There are three inequivalent Y sites. In the first Y site, Y(1) is bonded in an L-shaped geometry to one Mg(1), one Y(2), and one Y(3) atom. The Y(1)-Y(2) bond length is 4.16 Å. The Y(1)-Y(3) bond length is 0.76 Å. In the second Y site, Y(2) is bonded in a 7-coordinate geometry to one Mg(1), one Y(1), one Y(3), and four equivalent Y(2) atoms. The Y(2)-Y(3) bond length is 4.16 Å. All Y(2)-Y(2) bond lengths are 3.68 Å. In the third Y site, Y(3) is bonded in a distorted single-bond geometry to one Y(1) and one Y(2) atom.