The material structure described by Sr2Mg3Al crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 12-coordinate geometry to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Al(1) atoms. In the second Sr site, Sr(2) is bonded in a 12-coordinate geometry to three equivalent Mg(1), six equivalent Mg(2), and three equivalent Al(1) atoms. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Sr(2), four equivalent Sr(1), four equivalent Mg(1), and two equivalent Al(1) atoms to form distorted MgSr6Mg4Al2 cuboctahedra that share corners with four equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, corners with four equivalent Al(1)Sr6Mg6 cuboctahedra, corners with ten equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, edges with two equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, edges with four equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, faces with four equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, faces with six equivalent Al(1)Sr6Mg6 cuboctahedra, and faces with eight equivalent Mg(1)Sr6Mg4Al2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Sr(1), four equivalent Sr(2), four equivalent Mg(2), and two equivalent Al(1) atoms to form MgSr6Mg4Al2 cuboctahedra that share corners with four equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, corners with four equivalent Al(1)Sr6Mg6 cuboctahedra, corners with ten equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, edges with two equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, edges with four equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, faces with four equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, faces with six equivalent Al(1)Sr6Mg6 cuboctahedra, and faces with eight equivalent Mg(2)Sr6Mg4Al2 cuboctahedra. Al(1) is bonded to three equivalent Sr(1), three equivalent Sr(2), three equivalent Mg(1), and three equivalent Mg(2) atoms to form AlSr6Mg6 cuboctahedra that share corners with three equivalent Al(1)Sr6Mg6 cuboctahedra, corners with six equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, corners with six equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, edges with six equivalent Al(1)Sr6Mg6 cuboctahedra,  a faceface with one Al(1)Sr6Mg6 cuboctahedra, faces with nine equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, and faces with nine equivalent Mg(2)Sr6Mg4Al2 cuboctahedra. is represented by the CIF file [CIF]
data_Sr2Mg3Al
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.237
_cell_length_b   6.237
_cell_length_c   20.815
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   701.162
_cell_formula_units_Z   4
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
  Sr  Sr0  1  0.333  0.667  0.655  1.0
  Sr  Sr1  1  0.667  0.333  0.345  1.0
  Sr  Sr2  1  0.667  0.333  0.155  1.0
  Sr  Sr3  1  0.333  0.667  0.845  1.0
  Sr  Sr4  1  0.000  0.000  0.097  1.0
  Sr  Sr5  1  0.000  0.000  0.903  1.0
  Sr  Sr6  1  0.000  0.000  0.597  1.0
  Sr  Sr7  1  0.000  0.000  0.403  1.0
  Mg  Mg8  1  0.168  0.335  0.250  1.0
  Mg  Mg9  1  0.832  0.665  0.750  1.0
  Mg  Mg10  1  0.665  0.832  0.250  1.0
  Mg  Mg11  1  0.335  0.168  0.750  1.0
  Mg  Mg12  1  0.168  0.832  0.250  1.0
  Mg  Mg13  1  0.832  0.168  0.750  1.0
  Mg  Mg14  1  0.500  0.000  0.000  1.0
  Mg  Mg15  1  0.000  0.500  0.000  1.0
  Mg  Mg16  1  0.500  0.000  0.500  1.0
  Mg  Mg17  1  0.500  0.500  0.000  1.0
  Mg  Mg18  1  0.000  0.500  0.500  1.0
  Mg  Mg19  1  0.500  0.500  0.500  1.0
  Al  Al20  1  0.333  0.667  0.131  1.0
  Al  Al21  1  0.667  0.333  0.869  1.0
  Al  Al22  1  0.667  0.333  0.631  1.0
  Al  Al23  1  0.333  0.667  0.369  1.0
[/CIF]
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The material structure described by Sr2Mg3Al crystallizes in the hexagonal P6_3/mmc space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 12-coordinate geometry to three equivalent Mg(2), six equivalent Mg(1), and three equivalent Al(1) atoms. In the second Sr site, Sr(2) is bonded in a 12-coordinate geometry to three equivalent Mg(1), six equivalent Mg(2), and three equivalent Al(1) atoms. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent Sr(2), four equivalent Sr(1), four equivalent Mg(1), and two equivalent Al(1) atoms to form distorted MgSr6Mg4Al2 cuboctahedra that share corners with four equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, corners with four equivalent Al(1)Sr6Mg6 cuboctahedra, corners with ten equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, edges with two equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, edges with four equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, faces with four equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, faces with six equivalent Al(1)Sr6Mg6 cuboctahedra, and faces with eight equivalent Mg(1)Sr6Mg4Al2 cuboctahedra. In the second Mg site, Mg(2) is bonded to two equivalent Sr(1), four equivalent Sr(2), four equivalent Mg(2), and two equivalent Al(1) atoms to form MgSr6Mg4Al2 cuboctahedra that share corners with four equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, corners with four equivalent Al(1)Sr6Mg6 cuboctahedra, corners with ten equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, edges with two equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, edges with four equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, faces with four equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, faces with six equivalent Al(1)Sr6Mg6 cuboctahedra, and faces with eight equivalent Mg(2)Sr6Mg4Al2 cuboctahedra. Al(1) is bonded to three equivalent Sr(1), three equivalent Sr(2), three equivalent Mg(1), and three equivalent Mg(2) atoms to form AlSr6Mg6 cuboctahedra that share corners with three equivalent Al(1)Sr6Mg6 cuboctahedra, corners with six equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, corners with six equivalent Mg(2)Sr6Mg4Al2 cuboctahedra, edges with six equivalent Al(1)Sr6Mg6 cuboctahedra,  a faceface with one Al(1)Sr6Mg6 cuboctahedra, faces with nine equivalent Mg(1)Sr6Mg4Al2 cuboctahedra, and faces with nine equivalent Mg(2)Sr6Mg4Al2 cuboctahedra. is represented by the CIF file [CIF]
data_Sr2Mg3Al
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.237
_cell_length_b   6.237
_cell_length_c   20.815
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   701.162
_cell_formula_units_Z   4
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
  Sr  Sr0  1  0.333  0.667  0.655  1.0
  Sr  Sr1  1  0.667  0.333  0.345  1.0
  Sr  Sr2  1  0.667  0.333  0.155  1.0
  Sr  Sr3  1  0.333  0.667  0.845  1.0
  Sr  Sr4  1  0.000  0.000  0.097  1.0
  Sr  Sr5  1  0.000  0.000  0.903  1.0
  Sr  Sr6  1  0.000  0.000  0.597  1.0
  Sr  Sr7  1  0.000  0.000  0.403  1.0
  Mg  Mg8  1  0.168  0.335  0.250  1.0
  Mg  Mg9  1  0.832  0.665  0.750  1.0
  Mg  Mg10  1  0.665  0.832  0.250  1.0
  Mg  Mg11  1  0.335  0.168  0.750  1.0
  Mg  Mg12  1  0.168  0.832  0.250  1.0
  Mg  Mg13  1  0.832  0.168  0.750  1.0
  Mg  Mg14  1  0.500  0.000  0.000  1.0
  Mg  Mg15  1  0.000  0.500  0.000  1.0
  Mg  Mg16  1  0.500  0.000  0.500  1.0
  Mg  Mg17  1  0.500  0.500  0.000  1.0
  Mg  Mg18  1  0.000  0.500  0.500  1.0
  Mg  Mg19  1  0.500  0.500  0.500  1.0
  Al  Al20  1  0.333  0.667  0.131  1.0
  Al  Al21  1  0.667  0.333  0.869  1.0
  Al  Al22  1  0.667  0.333  0.631  1.0
  Al  Al23  1  0.333  0.667  0.369  1.0
[/CIF]
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