The structure described by Mg16CoAl12 crystallizes in the trigonal R3m space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(5), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. In the second Mg site, Mg(2) is bonded to one Mg(1), two equivalent Mg(4), four equivalent Mg(5), one Al(2), and four equivalent Al(3) atoms to form a mixture of distorted corner and edge-sharing MgMg7Al5 cuboctahedra. In the third Mg site, Mg(3) is bonded in a distorted single-bond geometry to three equivalent Mg(1), one Co(1), three equivalent Al(2), and six equivalent Al(3) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to two equivalent Mg(2), one Co(1), one Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. In the fifth Mg site, Mg(5) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Mg(2), one Al(2), two equivalent Al(1), and two equivalent Al(3) atoms. Co(1) is bonded in a 10-coordinate geometry to one Mg(3), three equivalent Mg(4), and six equivalent Al(3) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to one Mg(4), two equivalent Mg(1), four equivalent Mg(5), one Al(2), and two equivalent Al(3) atoms. In the second Al site, Al(2) is bonded in a 11-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(1), two equivalent Mg(4), two equivalent Mg(5), one Al(1), and two equivalent Al(2) atoms. In the third Al site, Al(3) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), two equivalent Mg(2), two equivalent Mg(5), one Co(1), one Al(1), and two equivalent Al(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg16Al12Co
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.211
_cell_length_b   9.010
_cell_length_c   9.010
_cell_angle_alpha   109.015
_cell_angle_beta   109.924
_cell_angle_gamma   109.924
_symmetry_Int_Tables_number   1
_cell_volume   572.363
_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  0.003  0.352  1.000  1.0
  Mg  Mg1  1  0.319  0.593  0.000  1.0
  Mg  Mg2  1  0.991  0.000  0.000  1.0
  Mg  Mg3  1  0.573  0.267  0.000  1.0
  Mg  Mg4  1  0.573  0.000  0.267  1.0
  Mg  Mg5  1  0.683  0.676  0.279  1.0
  Mg  Mg6  1  0.007  0.603  0.324  1.0
  Mg  Mg7  1  0.003  0.000  0.352  1.0
  Mg  Mg8  1  0.404  0.721  0.397  1.0
  Mg  Mg9  1  0.727  0.407  0.407  1.0
  Mg  Mg10  1  0.319  0.000  0.593  1.0
  Mg  Mg11  1  0.007  0.324  0.603  1.0
  Mg  Mg12  1  0.651  0.648  0.648  1.0
  Mg  Mg13  1  0.683  0.279  0.676  1.0
  Mg  Mg14  1  0.404  0.397  0.721  1.0
  Mg  Mg15  1  0.306  0.733  0.733  1.0
  Al  Al16  1  0.812  0.615  1.000  1.0
  Al  Al17  1  0.649  0.810  1.000  1.0
  Al  Al18  1  0.186  0.821  0.177  1.0
  Al  Al19  1  0.366  0.357  0.179  1.0
  Al  Al20  1  0.839  0.190  0.190  1.0
  Al  Al21  1  0.366  0.179  0.357  1.0
  Al  Al22  1  0.197  0.385  0.385  1.0
  Al  Al23  1  0.812  0.000  0.615  1.0
  Al  Al24  1  0.009  0.823  0.643  1.0
  Al  Al25  1  0.649  1.000  0.810  1.0
  Al  Al26  1  0.186  0.177  0.821  1.0
  Al  Al27  1  0.009  0.643  0.823  1.0
  Co  Co28  1  0.267  0.000  0.000  1.0
[/CIF]
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The structure described by Mg16CoAl12 crystallizes in the trigonal R3m space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 10-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(5), two equivalent Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. In the second Mg site, Mg(2) is bonded to one Mg(1), two equivalent Mg(4), four equivalent Mg(5), one Al(2), and four equivalent Al(3) atoms to form a mixture of distorted corner and edge-sharing MgMg7Al5 cuboctahedra. In the third Mg site, Mg(3) is bonded in a distorted single-bond geometry to three equivalent Mg(1), one Co(1), three equivalent Al(2), and six equivalent Al(3) atoms. In the fourth Mg site, Mg(4) is bonded in a 6-coordinate geometry to two equivalent Mg(2), one Co(1), one Al(1), two equivalent Al(2), and two equivalent Al(3) atoms. In the fifth Mg site, Mg(5) is bonded in a 5-coordinate geometry to one Mg(1), two equivalent Mg(2), one Al(2), two equivalent Al(1), and two equivalent Al(3) atoms. Co(1) is bonded in a 10-coordinate geometry to one Mg(3), three equivalent Mg(4), and six equivalent Al(3) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 10-coordinate geometry to one Mg(4), two equivalent Mg(1), four equivalent Mg(5), one Al(2), and two equivalent Al(3) atoms. In the second Al site, Al(2) is bonded in a 11-coordinate geometry to one Mg(2), one Mg(3), two equivalent Mg(1), two equivalent Mg(4), two equivalent Mg(5), one Al(1), and two equivalent Al(2) atoms. In the third Al site, Al(3) is bonded in a 11-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), two equivalent Mg(2), two equivalent Mg(5), one Co(1), one Al(1), and two equivalent Al(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg16Al12Co
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.211
_cell_length_b   9.010
_cell_length_c   9.010
_cell_angle_alpha   109.015
_cell_angle_beta   109.924
_cell_angle_gamma   109.924
_symmetry_Int_Tables_number   1
_cell_volume   572.363
_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  0.003  0.352  1.000  1.0
  Mg  Mg1  1  0.319  0.593  0.000  1.0
  Mg  Mg2  1  0.991  0.000  0.000  1.0
  Mg  Mg3  1  0.573  0.267  0.000  1.0
  Mg  Mg4  1  0.573  0.000  0.267  1.0
  Mg  Mg5  1  0.683  0.676  0.279  1.0
  Mg  Mg6  1  0.007  0.603  0.324  1.0
  Mg  Mg7  1  0.003  0.000  0.352  1.0
  Mg  Mg8  1  0.404  0.721  0.397  1.0
  Mg  Mg9  1  0.727  0.407  0.407  1.0
  Mg  Mg10  1  0.319  0.000  0.593  1.0
  Mg  Mg11  1  0.007  0.324  0.603  1.0
  Mg  Mg12  1  0.651  0.648  0.648  1.0
  Mg  Mg13  1  0.683  0.279  0.676  1.0
  Mg  Mg14  1  0.404  0.397  0.721  1.0
  Mg  Mg15  1  0.306  0.733  0.733  1.0
  Al  Al16  1  0.812  0.615  1.000  1.0
  Al  Al17  1  0.649  0.810  1.000  1.0
  Al  Al18  1  0.186  0.821  0.177  1.0
  Al  Al19  1  0.366  0.357  0.179  1.0
  Al  Al20  1  0.839  0.190  0.190  1.0
  Al  Al21  1  0.366  0.179  0.357  1.0
  Al  Al22  1  0.197  0.385  0.385  1.0
  Al  Al23  1  0.812  0.000  0.615  1.0
  Al  Al24  1  0.009  0.823  0.643  1.0
  Al  Al25  1  0.649  1.000  0.810  1.0
  Al  Al26  1  0.186  0.177  0.821  1.0
  Al  Al27  1  0.009  0.643  0.823  1.0
  Co  Co28  1  0.267  0.000  0.000  1.0
[/CIF]
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