The material structure described by Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic Cm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 9-coordinate geometry to one Si(1), two equivalent Si(10), three equivalent Si(11), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one Si(2), two equivalent Si(4), two equivalent Si(5), and three equivalent Si(12) atoms. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to one Si(11), two equivalent Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to one Si(12), two equivalent Si(1), two equivalent Si(4), and three equivalent Si(2) atoms. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to one Si(7), two equivalent Si(12), two equivalent Si(9), and three equivalent Si(5) atoms. In the sixth Mg site, Mg(6) is bonded in a 8-coordinate geometry to one Si(11), one Si(8), three equivalent Si(10), and three equivalent Si(6) atoms. In the seventh Mg site, Mg(7) is bonded in a 6-coordinate geometry to one Si(9), two equivalent Si(8), and three equivalent Si(7) atoms. In the eighth Mg site, Mg(8) is bonded in a 7-coordinate geometry to two equivalent Si(6), two equivalent Si(7), and three equivalent Si(8) atoms. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(4), three equivalent Mg(3), one Si(2), and two equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), three equivalent Mg(4), one Si(1), and two equivalent Si(4) atoms. In the third Si site, Si(3) is bonded in a distorted q6 geometry to two equivalent Mg(3), three equivalent Mg(1), two equivalent Si(1), and two equivalent Si(11) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(12), and two equivalent Si(2) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent Mg(2), three equivalent Mg(5), one Si(12), and two equivalent Si(9) atoms. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to two equivalent Mg(8), three equivalent Mg(6), one Si(8), and two equivalent Si(10) atoms. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(8), three equivalent Mg(7), one Si(8), and two equivalent Si(9) atoms. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Mg(6), two equivalent Mg(7), three equivalent Mg(8), one Si(6), and one Si(7) atom. In the ninth Si site, Si(9) is bonded in a 7-coordinate geometry to one Mg(7), two equivalent Mg(5), two equivalent Si(5), and two equivalent Si(7) atoms. In the tenth Si site, Si(10) is bonded in a 8-coordinate geometry to two equivalent Mg(1), three equivalent Mg(6), one Si(11), and two equivalent Si(6) atoms. In the eleventh Si site, Si(11) is bonded in a 8-coordinate geometry to one Mg(3), one Mg(6), three equivalent Mg(1), one Si(10), and two equivalent Si(3) atoms. In the twelfth Si site, Si(12) is bonded in a 9-coordinate geometry to one Mg(4), two equivalent Mg(5), three equivalent Mg(2), one Si(5), and two equivalent Si(4) atoms. is represented by the CIF file [CIF]
data_Mg2Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.252
_cell_length_b   5.252
_cell_length_c   19.808
_cell_angle_alpha   80.802
_cell_angle_beta   80.802
_cell_angle_gamma   43.248
_symmetry_Int_Tables_number   1
_cell_volume   368.754
_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  0.495  0.495  0.174  1.0
  Mg  Mg1  1  0.691  0.691  0.809  1.0
  Mg  Mg2  1  0.933  0.933  0.048  1.0
  Mg  Mg3  1  0.259  0.259  0.942  1.0
  Mg  Mg4  1  0.021  0.021  0.707  1.0
  Mg  Mg5  1  0.588  0.588  0.319  1.0
  Mg  Mg6  1  0.943  0.943  0.547  1.0
  Mg  Mg7  1  0.674  0.674  0.463  1.0
  Si  Si8  1  0.651  0.651  0.045  1.0
  Si  Si9  1  0.545  0.545  0.945  1.0
  Si  Si10  1  0.228  0.228  0.120  1.0
  Si  Si11  1  0.975  0.975  0.875  1.0
  Si  Si12  1  0.316  0.316  0.700  1.0
  Si  Si13  1  0.281  0.281  0.358  1.0
  Si  Si14  1  0.210  0.210  0.562  1.0
  Si  Si15  1  0.392  0.392  0.457  1.0
  Si  Si16  1  0.714  0.714  0.642  1.0
  Si  Si17  1  0.891  0.891  0.289  1.0
  Si  Si18  1  0.774  0.774  0.192  1.0
  Si  Si19  1  0.402  0.402  0.807  1.0
[/CIF]
.
The material structure described by Mg2Si3 is Magnesium tetraboride-like structured and crystallizes in the monoclinic Cm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 9-coordinate geometry to one Si(1), two equivalent Si(10), three equivalent Si(11), and three equivalent Si(3) atoms. In the second Mg site, Mg(2) is bonded in a 8-coordinate geometry to one Si(2), two equivalent Si(4), two equivalent Si(5), and three equivalent Si(12) atoms. In the third Mg site, Mg(3) is bonded in a 8-coordinate geometry to one Si(11), two equivalent Si(2), two equivalent Si(3), and three equivalent Si(1) atoms. In the fourth Mg site, Mg(4) is bonded in a 8-coordinate geometry to one Si(12), two equivalent Si(1), two equivalent Si(4), and three equivalent Si(2) atoms. In the fifth Mg site, Mg(5) is bonded in a 7-coordinate geometry to one Si(7), two equivalent Si(12), two equivalent Si(9), and three equivalent Si(5) atoms. In the sixth Mg site, Mg(6) is bonded in a 8-coordinate geometry to one Si(11), one Si(8), three equivalent Si(10), and three equivalent Si(6) atoms. In the seventh Mg site, Mg(7) is bonded in a 6-coordinate geometry to one Si(9), two equivalent Si(8), and three equivalent Si(7) atoms. In the eighth Mg site, Mg(8) is bonded in a 7-coordinate geometry to two equivalent Si(6), two equivalent Si(7), and three equivalent Si(8) atoms. There are twelve inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to one Mg(1), two equivalent Mg(4), three equivalent Mg(3), one Si(2), and two equivalent Si(3) atoms. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to one Mg(2), two equivalent Mg(3), three equivalent Mg(4), one Si(1), and two equivalent Si(4) atoms. In the third Si site, Si(3) is bonded in a distorted q6 geometry to two equivalent Mg(3), three equivalent Mg(1), two equivalent Si(1), and two equivalent Si(11) atoms. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to two equivalent Mg(2), two equivalent Mg(4), two equivalent Si(12), and two equivalent Si(2) atoms. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to two equivalent Mg(2), three equivalent Mg(5), one Si(12), and two equivalent Si(9) atoms. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to two equivalent Mg(8), three equivalent Mg(6), one Si(8), and two equivalent Si(10) atoms. In the seventh Si site, Si(7) is bonded in a 9-coordinate geometry to one Mg(5), two equivalent Mg(8), three equivalent Mg(7), one Si(8), and two equivalent Si(9) atoms. In the eighth Si site, Si(8) is bonded in a 8-coordinate geometry to one Mg(6), two equivalent Mg(7), three equivalent Mg(8), one Si(6), and one Si(7) atom. In the ninth Si site, Si(9) is bonded in a 7-coordinate geometry to one Mg(7), two equivalent Mg(5), two equivalent Si(5), and two equivalent Si(7) atoms. In the tenth Si site, Si(10) is bonded in a 8-coordinate geometry to two equivalent Mg(1), three equivalent Mg(6), one Si(11), and two equivalent Si(6) atoms. In the eleventh Si site, Si(11) is bonded in a 8-coordinate geometry to one Mg(3), one Mg(6), three equivalent Mg(1), one Si(10), and two equivalent Si(3) atoms. In the twelfth Si site, Si(12) is bonded in a 9-coordinate geometry to one Mg(4), two equivalent Mg(5), three equivalent Mg(2), one Si(5), and two equivalent Si(4) atoms. is represented by the CIF file [CIF]
data_Mg2Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.252
_cell_length_b   5.252
_cell_length_c   19.808
_cell_angle_alpha   80.802
_cell_angle_beta   80.802
_cell_angle_gamma   43.248
_symmetry_Int_Tables_number   1
_cell_volume   368.754
_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  0.495  0.495  0.174  1.0
  Mg  Mg1  1  0.691  0.691  0.809  1.0
  Mg  Mg2  1  0.933  0.933  0.048  1.0
  Mg  Mg3  1  0.259  0.259  0.942  1.0
  Mg  Mg4  1  0.021  0.021  0.707  1.0
  Mg  Mg5  1  0.588  0.588  0.319  1.0
  Mg  Mg6  1  0.943  0.943  0.547  1.0
  Mg  Mg7  1  0.674  0.674  0.463  1.0
  Si  Si8  1  0.651  0.651  0.045  1.0
  Si  Si9  1  0.545  0.545  0.945  1.0
  Si  Si10  1  0.228  0.228  0.120  1.0
  Si  Si11  1  0.975  0.975  0.875  1.0
  Si  Si12  1  0.316  0.316  0.700  1.0
  Si  Si13  1  0.281  0.281  0.358  1.0
  Si  Si14  1  0.210  0.210  0.562  1.0
  Si  Si15  1  0.392  0.392  0.457  1.0
  Si  Si16  1  0.714  0.714  0.642  1.0
  Si  Si17  1  0.891  0.891  0.289  1.0
  Si  Si18  1  0.774  0.774  0.192  1.0
  Si  Si19  1  0.402  0.402  0.807  1.0
[/CIF]
.