The crystal structure described by Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to one Si(1), three equivalent Si(2), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(2), two equivalent Si(3), and four equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(1), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), three equivalent Mg(1), two equivalent Si(1), and two equivalent Si(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Mg(2), three equivalent Mg(1), two equivalent Si(2), and two equivalent Si(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.059
_cell_length_b   9.059
_cell_length_c   5.884
_cell_angle_alpha   75.270
_cell_angle_beta   75.270
_cell_angle_gamma   22.435
_symmetry_Int_Tables_number   1
_cell_volume   177.965
_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
  Mg  Mg0  1  0.700  0.700  0.179  1.0
  Mg  Mg1  1  0.300  0.300  0.821  1.0
  Mg  Mg2  1  0.078  0.078  0.535  1.0
  Mg  Mg3  1  0.922  0.922  0.465  1.0
  Si  Si4  1  0.538  0.538  0.149  1.0
  Si  Si5  1  0.462  0.462  0.851  1.0
  Si  Si6  1  0.131  0.131  0.939  1.0
  Si  Si7  1  0.869  0.869  0.061  1.0
  Si  Si8  1  0.699  0.699  0.633  1.0
  Si  Si9  1  0.301  0.301  0.367  1.0
[/CIF]
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The crystal structure described by Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to one Si(1), three equivalent Si(2), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one Si(2), two equivalent Si(3), and four equivalent Si(1) atoms. There are three inequivalent Si sites. In the first Si site, Si(1) is bonded in a 8-coordinate geometry to one Mg(1), four equivalent Mg(2), one Si(1), and two equivalent Si(2) atoms. In the second Si site, Si(2) is bonded in a 8-coordinate geometry to one Mg(2), three equivalent Mg(1), two equivalent Si(1), and two equivalent Si(3) atoms. In the third Si site, Si(3) is bonded in a 9-coordinate geometry to two equivalent Mg(2), three equivalent Mg(1), two equivalent Si(2), and two equivalent Si(3) atoms. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   9.059
_cell_length_b   9.059
_cell_length_c   5.884
_cell_angle_alpha   75.270
_cell_angle_beta   75.270
_cell_angle_gamma   22.435
_symmetry_Int_Tables_number   1
_cell_volume   177.965
_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
  Mg  Mg0  1  0.700  0.700  0.179  1.0
  Mg  Mg1  1  0.300  0.300  0.821  1.0
  Mg  Mg2  1  0.078  0.078  0.535  1.0
  Mg  Mg3  1  0.922  0.922  0.465  1.0
  Si  Si4  1  0.538  0.538  0.149  1.0
  Si  Si5  1  0.462  0.462  0.851  1.0
  Si  Si6  1  0.131  0.131  0.939  1.0
  Si  Si7  1  0.869  0.869  0.061  1.0
  Si  Si8  1  0.699  0.699  0.633  1.0
  Si  Si9  1  0.301  0.301  0.367  1.0
[/CIF]
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