The crystal structure described by Sr2Mg1 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 3-coordinate geometry to three equivalent Sr(2) and three equivalent Mg(1) atoms. In the second Sr site, Sr(2) is bonded to three equivalent Sr(1) and nine equivalent Sr(2) atoms to form SrSr12 cuboctahedra that share corners with six equivalent Sr(2)Sr12 cuboctahedra, corners with six equivalent Mg(1)Sr3Mg3 pentagonal pyramids, edges with twelve equivalent Sr(2)Sr12 cuboctahedra, faces with twelve equivalent Sr(2)Sr12 cuboctahedra, and  a faceface with one Mg(1)Sr3Mg3 pentagonal pyramid. Mg(1) is bonded to three equivalent Sr(1) and three equivalent Mg(1) atoms to form distorted MgSr3Mg3 pentagonal pyramids that share corners with six equivalent Sr(2)Sr12 cuboctahedra, edges with six equivalent Mg(1)Sr3Mg3 pentagonal pyramids, and  a faceface with one Sr(2)Sr12 cuboctahedra. is represented by the CIF file [CIF]
data_Sr2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.228
_cell_length_b   4.228
_cell_length_c   17.599
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   272.414
_cell_formula_units_Z   2
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  0.797  1.0
  Sr  Sr1  1  0.667  0.333  0.597  1.0
  Sr  Sr2  1  0.333  0.667  0.403  1.0
  Sr  Sr3  1  0.667  0.333  0.203  1.0
  Mg  Mg4  1  0.667  0.333  0.948  1.0
  Mg  Mg5  1  0.333  0.667  0.052  1.0
[/CIF]
.
The crystal structure described by Sr2Mg1 crystallizes in the trigonal P-3m1 space group. There are two inequivalent Sr sites. In the first Sr site, Sr(1) is bonded in a 3-coordinate geometry to three equivalent Sr(2) and three equivalent Mg(1) atoms. In the second Sr site, Sr(2) is bonded to three equivalent Sr(1) and nine equivalent Sr(2) atoms to form SrSr12 cuboctahedra that share corners with six equivalent Sr(2)Sr12 cuboctahedra, corners with six equivalent Mg(1)Sr3Mg3 pentagonal pyramids, edges with twelve equivalent Sr(2)Sr12 cuboctahedra, faces with twelve equivalent Sr(2)Sr12 cuboctahedra, and  a faceface with one Mg(1)Sr3Mg3 pentagonal pyramid. Mg(1) is bonded to three equivalent Sr(1) and three equivalent Mg(1) atoms to form distorted MgSr3Mg3 pentagonal pyramids that share corners with six equivalent Sr(2)Sr12 cuboctahedra, edges with six equivalent Mg(1)Sr3Mg3 pentagonal pyramids, and  a faceface with one Sr(2)Sr12 cuboctahedra. is represented by the CIF file [CIF]
data_Sr2Mg
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.228
_cell_length_b   4.228
_cell_length_c   17.599
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   272.414
_cell_formula_units_Z   2
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  0.797  1.0
  Sr  Sr1  1  0.667  0.333  0.597  1.0
  Sr  Sr2  1  0.333  0.667  0.403  1.0
  Sr  Sr3  1  0.667  0.333  0.203  1.0
  Mg  Mg4  1  0.667  0.333  0.948  1.0
  Mg  Mg5  1  0.333  0.667  0.052  1.0
[/CIF]
.