The crystal structure described by Mg3Tl is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to eight equivalent Mg(2) and four equivalent Tl(1) atoms to form MgMg8Tl4 cuboctahedra that share corners with four equivalent Mg(1)Mg8Tl4 cuboctahedra, corners with eight equivalent Tl(1)Mg12 cuboctahedra, edges with eight equivalent Mg(1)Mg8Tl4 cuboctahedra, edges with sixteen equivalent Mg(2)Mg8Tl4 cuboctahedra, faces with four equivalent Mg(1)Mg8Tl4 cuboctahedra, faces with six equivalent Tl(1)Mg12 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Tl4 cuboctahedra. In the second Mg site, Mg(2) is bonded to four equivalent Mg(1), four equivalent Mg(2), and four equivalent Tl(1) atoms to form MgMg8Tl4 cuboctahedra that share corners with twelve equivalent Mg(2)Mg8Tl4 cuboctahedra, edges with eight equivalent Mg(1)Mg8Tl4 cuboctahedra, edges with eight equivalent Mg(2)Mg8Tl4 cuboctahedra, edges with eight equivalent Tl(1)Mg12 cuboctahedra, faces with four equivalent Mg(1)Mg8Tl4 cuboctahedra, faces with four equivalent Tl(1)Mg12 cuboctahedra, and faces with ten equivalent Mg(2)Mg8Tl4 cuboctahedra. Tl(1) is bonded to four equivalent Mg(1) and eight equivalent Mg(2) atoms to form TlMg12 cuboctahedra that share corners with four equivalent Tl(1)Mg12 cuboctahedra, corners with eight equivalent Mg(1)Mg8Tl4 cuboctahedra, edges with eight equivalent Tl(1)Mg12 cuboctahedra, edges with sixteen equivalent Mg(2)Mg8Tl4 cuboctahedra, faces with four equivalent Tl(1)Mg12 cuboctahedra, faces with six equivalent Mg(1)Mg8Tl4 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Tl4 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Tl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.504
_cell_length_b   5.504
_cell_length_c   5.504
_cell_angle_alpha   131.791
_cell_angle_beta   131.791
_cell_angle_gamma   70.560
_symmetry_Int_Tables_number   1
_cell_volume   90.834
_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  0.500  0.500  0.000  1.0
  Mg  Mg1  1  0.750  0.250  0.500  1.0
  Mg  Mg2  1  0.250  0.750  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
[/CIF]
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The crystal structure described by Mg3Tl is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to eight equivalent Mg(2) and four equivalent Tl(1) atoms to form MgMg8Tl4 cuboctahedra that share corners with four equivalent Mg(1)Mg8Tl4 cuboctahedra, corners with eight equivalent Tl(1)Mg12 cuboctahedra, edges with eight equivalent Mg(1)Mg8Tl4 cuboctahedra, edges with sixteen equivalent Mg(2)Mg8Tl4 cuboctahedra, faces with four equivalent Mg(1)Mg8Tl4 cuboctahedra, faces with six equivalent Tl(1)Mg12 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Tl4 cuboctahedra. In the second Mg site, Mg(2) is bonded to four equivalent Mg(1), four equivalent Mg(2), and four equivalent Tl(1) atoms to form MgMg8Tl4 cuboctahedra that share corners with twelve equivalent Mg(2)Mg8Tl4 cuboctahedra, edges with eight equivalent Mg(1)Mg8Tl4 cuboctahedra, edges with eight equivalent Mg(2)Mg8Tl4 cuboctahedra, edges with eight equivalent Tl(1)Mg12 cuboctahedra, faces with four equivalent Mg(1)Mg8Tl4 cuboctahedra, faces with four equivalent Tl(1)Mg12 cuboctahedra, and faces with ten equivalent Mg(2)Mg8Tl4 cuboctahedra. Tl(1) is bonded to four equivalent Mg(1) and eight equivalent Mg(2) atoms to form TlMg12 cuboctahedra that share corners with four equivalent Tl(1)Mg12 cuboctahedra, corners with eight equivalent Mg(1)Mg8Tl4 cuboctahedra, edges with eight equivalent Tl(1)Mg12 cuboctahedra, edges with sixteen equivalent Mg(2)Mg8Tl4 cuboctahedra, faces with four equivalent Tl(1)Mg12 cuboctahedra, faces with six equivalent Mg(1)Mg8Tl4 cuboctahedra, and faces with eight equivalent Mg(2)Mg8Tl4 cuboctahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg3Tl
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.504
_cell_length_b   5.504
_cell_length_c   5.504
_cell_angle_alpha   131.791
_cell_angle_beta   131.791
_cell_angle_gamma   70.560
_symmetry_Int_Tables_number   1
_cell_volume   90.834
_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  0.500  0.500  0.000  1.0
  Mg  Mg1  1  0.750  0.250  0.500  1.0
  Mg  Mg2  1  0.250  0.750  0.500  1.0
  Tl  Tl3  1  0.000  0.000  0.000  1.0
[/CIF]
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