The material described by Mg2Si is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to five equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded to four equivalent Si(1) atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. Si(1) is bonded in a 9-coordinate geometry to four equivalent Mg(2) and five equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.181
_cell_length_b   6.995
_cell_length_c   7.990
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   233.693
_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
  Mg  Mg0  1  0.750  0.468  0.665  1.0
  Mg  Mg1  1  0.750  0.968  0.835  1.0
  Mg  Mg2  1  0.250  0.532  0.335  1.0
  Mg  Mg3  1  0.250  0.032  0.165  1.0
  Mg  Mg4  1  0.750  0.361  0.060  1.0
  Mg  Mg5  1  0.750  0.861  0.440  1.0
  Mg  Mg6  1  0.250  0.639  0.940  1.0
  Mg  Mg7  1  0.250  0.139  0.560  1.0
  Si  Si8  1  0.750  0.247  0.375  1.0
  Si  Si9  1  0.750  0.747  0.125  1.0
  Si  Si10  1  0.250  0.753  0.625  1.0
  Si  Si11  1  0.250  0.253  0.875  1.0
[/CIF]
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The material described by Mg2Si is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to five equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded to four equivalent Si(1) atoms to form a mixture of distorted corner and edge-sharing MgSi4 tetrahedra. Si(1) is bonded in a 9-coordinate geometry to four equivalent Mg(2) and five equivalent Mg(1) atoms. is represented by the CIF card [CIF]
data_Mg2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   4.181
_cell_length_b   6.995
_cell_length_c   7.990
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   233.693
_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
  Mg  Mg0  1  0.750  0.468  0.665  1.0
  Mg  Mg1  1  0.750  0.968  0.835  1.0
  Mg  Mg2  1  0.250  0.532  0.335  1.0
  Mg  Mg3  1  0.250  0.032  0.165  1.0
  Mg  Mg4  1  0.750  0.361  0.060  1.0
  Mg  Mg5  1  0.750  0.861  0.440  1.0
  Mg  Mg6  1  0.250  0.639  0.940  1.0
  Mg  Mg7  1  0.250  0.139  0.560  1.0
  Si  Si8  1  0.750  0.247  0.375  1.0
  Si  Si9  1  0.750  0.747  0.125  1.0
  Si  Si10  1  0.250  0.753  0.625  1.0
  Si  Si11  1  0.250  0.253  0.875  1.0
[/CIF]
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