The material described by Mg7Y crystallizes in the hexagonal P-6m2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1,1)Y2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with four Mg(1,1)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with ten equivalent Mg(2)Y2Mg10 cuboctahedra. In the second Mg site, Mg(1) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1,1)Y2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with four Mg(1,1)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with ten equivalent Mg(2)Y2Mg10 cuboctahedra. In the third Mg site, Mg(1) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1,1)Y2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with four Mg(1,1)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with ten equivalent Mg(2)Y2Mg10 cuboctahedra. In the fourth Mg site, Mg(2) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Mg12 cuboctahedra; corners with fourteen equivalent Mg(2)Y2Mg10 cuboctahedra; edges with two equivalent Mg(3)Mg12 cuboctahedra; edges with four equivalent Mg(2)Y2Mg10 cuboctahedra; edges with four equivalent Y(1)Mg12 cuboctahedra; edges with eight Mg(1,1)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(2)Y2Mg10 cuboctahedra; and faces with ten Mg(1,1,1)Y2Mg10 cuboctahedra. In the fifth Mg site, Mg(3) is bonded to six Mg(1,1,1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(3)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Y2Mg10 cuboctahedra; edges with six equivalent Mg(2)Y2Mg10 cuboctahedra; edges with twelve Mg(1,1,1)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; faces with six equivalent Mg(2)Y2Mg10 cuboctahedra; and faces with six equivalent Y(1)Mg12 cuboctahedra. Y(1) is bonded to six Mg(1,1,1) and six equivalent Mg(2) atoms to form YMg12 cuboctahedra that share corners with six equivalent Y(1)Mg12 cuboctahedra; corners with twelve Mg(1,1,1)Y2Mg10 cuboctahedra; edges with six Mg(1,1,1)Y2Mg10 cuboctahedra; edges with twelve equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with six equivalent Mg(2)Y2Mg10 cuboctahedra. is represented by the CIF card [CIF]
data_YMg7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.586
_cell_length_b   6.586
_cell_length_c   5.154
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   193.626
_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  Y0  1  0.167  0.333  0.250  1.0
  Mg  Mg1  1  0.175  0.838  0.250  1.0
  Mg  Mg2  1  0.662  0.325  0.250  1.0
  Mg  Mg3  1  0.662  0.838  0.250  1.0
  Mg  Mg4  1  0.336  0.164  0.750  1.0
  Mg  Mg5  1  0.336  0.673  0.750  1.0
  Mg  Mg6  1  0.827  0.164  0.750  1.0
  Mg  Mg7  1  0.833  0.667  0.750  1.0
[/CIF]
.
The material described by Mg7Y crystallizes in the hexagonal P-6m2 space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1,1)Y2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with four Mg(1,1)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with ten equivalent Mg(2)Y2Mg10 cuboctahedra. In the second Mg site, Mg(1) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1,1)Y2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with four Mg(1,1)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with ten equivalent Mg(2)Y2Mg10 cuboctahedra. In the third Mg site, Mg(1) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Y(1)Mg12 cuboctahedra; corners with fourteen Mg(1,1,1)Y2Mg10 cuboctahedra; edges with two equivalent Y(1)Mg12 cuboctahedra; edges with four equivalent Mg(3)Mg12 cuboctahedra; edges with four Mg(1,1)Y2Mg10 cuboctahedra; edges with eight equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with ten equivalent Mg(2)Y2Mg10 cuboctahedra. In the fourth Mg site, Mg(2) is bonded to two equivalent Mg(3); four Mg(1,1); four equivalent Mg(2); and two equivalent Y(1) atoms to form MgY2Mg10 cuboctahedra that share corners with four equivalent Mg(3)Mg12 cuboctahedra; corners with fourteen equivalent Mg(2)Y2Mg10 cuboctahedra; edges with two equivalent Mg(3)Mg12 cuboctahedra; edges with four equivalent Mg(2)Y2Mg10 cuboctahedra; edges with four equivalent Y(1)Mg12 cuboctahedra; edges with eight Mg(1,1)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(2)Y2Mg10 cuboctahedra; and faces with ten Mg(1,1,1)Y2Mg10 cuboctahedra. In the fifth Mg site, Mg(3) is bonded to six Mg(1,1,1) and six equivalent Mg(2) atoms to form MgMg12 cuboctahedra that share corners with six equivalent Mg(3)Mg12 cuboctahedra; corners with twelve equivalent Mg(2)Y2Mg10 cuboctahedra; edges with six equivalent Mg(2)Y2Mg10 cuboctahedra; edges with twelve Mg(1,1,1)Y2Mg10 cuboctahedra; faces with two equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; faces with six equivalent Mg(2)Y2Mg10 cuboctahedra; and faces with six equivalent Y(1)Mg12 cuboctahedra. Y(1) is bonded to six Mg(1,1,1) and six equivalent Mg(2) atoms to form YMg12 cuboctahedra that share corners with six equivalent Y(1)Mg12 cuboctahedra; corners with twelve Mg(1,1,1)Y2Mg10 cuboctahedra; edges with six Mg(1,1,1)Y2Mg10 cuboctahedra; edges with twelve equivalent Mg(2)Y2Mg10 cuboctahedra; faces with two equivalent Y(1)Mg12 cuboctahedra; faces with six equivalent Mg(3)Mg12 cuboctahedra; faces with six Mg(1,1,1)Y2Mg10 cuboctahedra; and faces with six equivalent Mg(2)Y2Mg10 cuboctahedra. is represented by the CIF card [CIF]
data_YMg7
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.586
_cell_length_b   6.586
_cell_length_c   5.154
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   193.626
_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  Y0  1  0.167  0.333  0.250  1.0
  Mg  Mg1  1  0.175  0.838  0.250  1.0
  Mg  Mg2  1  0.662  0.325  0.250  1.0
  Mg  Mg3  1  0.662  0.838  0.250  1.0
  Mg  Mg4  1  0.336  0.164  0.750  1.0
  Mg  Mg5  1  0.336  0.673  0.750  1.0
  Mg  Mg6  1  0.827  0.164  0.750  1.0
  Mg  Mg7  1  0.833  0.667  0.750  1.0
[/CIF]
.