The crystal structure described by Bi2Mg2Sr crystallizes in the trigonal P-3m1 space group. Sr(1) is bonded to six equivalent Bi(1) atoms to form SrBi6 octahedra that share corners with twelve equivalent Mg(1)Bi4 tetrahedra, edges with six equivalent Sr(1)Bi6 octahedra, and edges with six equivalent Mg(1)Bi4 tetrahedra. Mg(1) is bonded to four equivalent Bi(1) atoms to form MgBi4 tetrahedra that share corners with six equivalent Sr(1)Bi6 octahedra, corners with six equivalent Mg(1)Bi4 tetrahedra, edges with three equivalent Sr(1)Bi6 octahedra, and edges with three equivalent Mg(1)Bi4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-54°. Bi(1) is bonded to three equivalent Sr(1) and four equivalent Mg(1) atoms to form a mixture of distorted corner and edge-sharing BiSr3Mg4 pentagonal bipyramids. is represented by the CIF card [CIF]
data_Sr(MgBi)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.830
_cell_length_b   4.830
_cell_length_c   7.983
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   161.263
_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
  Sr  Sr0  1  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.667  0.333  0.375  1.0
  Mg  Mg2  1  0.333  0.667  0.625  1.0
  Bi  Bi3  1  0.667  0.333  0.747  1.0
  Bi  Bi4  1  0.333  0.667  0.253  1.0
[/CIF]
.
The crystal structure described by Bi2Mg2Sr crystallizes in the trigonal P-3m1 space group. Sr(1) is bonded to six equivalent Bi(1) atoms to form SrBi6 octahedra that share corners with twelve equivalent Mg(1)Bi4 tetrahedra, edges with six equivalent Sr(1)Bi6 octahedra, and edges with six equivalent Mg(1)Bi4 tetrahedra. Mg(1) is bonded to four equivalent Bi(1) atoms to form MgBi4 tetrahedra that share corners with six equivalent Sr(1)Bi6 octahedra, corners with six equivalent Mg(1)Bi4 tetrahedra, edges with three equivalent Sr(1)Bi6 octahedra, and edges with three equivalent Mg(1)Bi4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-54°. Bi(1) is bonded to three equivalent Sr(1) and four equivalent Mg(1) atoms to form a mixture of distorted corner and edge-sharing BiSr3Mg4 pentagonal bipyramids. is represented by the CIF card [CIF]
data_Sr(MgBi)2
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.830
_cell_length_b   4.830
_cell_length_c   7.983
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   161.263
_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
  Sr  Sr0  1  0.000  0.000  0.000  1.0
  Mg  Mg1  1  0.667  0.333  0.375  1.0
  Mg  Mg2  1  0.333  0.667  0.625  1.0
  Bi  Bi3  1  0.667  0.333  0.747  1.0
  Bi  Bi4  1  0.333  0.667  0.253  1.0
[/CIF]
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