The crystal structure described by Mg4Si3 is alpha Pu-derived structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to one Si(1), one Si(4), one Si(5), and one Si(6) atom. In the third Mg site, Mg(3) is bonded in a distorted tetrahedral geometry to one Si(2), one Si(3), one Si(4), and one Si(5) atom. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), and one Si(5) atom. In the fifth Mg site, Mg(5) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(4), and one Si(6) atom. In the seventh Mg site, Mg(7) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the eighth Mg site, Mg(8) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and one Si(6) atom. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(2), one Mg(4), one Mg(5), one Mg(6), one Si(2), and one Si(5) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Mg(7), one Mg(8), one Si(1), and one Si(6) atom. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(7), one Mg(8), and one Si(6) atom. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(7), and one Mg(8) atom. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(7), one Mg(8), and one Si(1) atom. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(5), one Mg(6), one Mg(7), one Mg(8), one Si(2), and one Si(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.582
_cell_length_b   6.631
_cell_length_c   6.424
_cell_angle_alpha   101.857
_cell_angle_beta   80.218
_cell_angle_gamma   66.535
_symmetry_Int_Tables_number   1
_cell_volume   278.313
_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  0.545  0.831  0.515  1.0
  Mg  Mg1  1  0.859  0.156  0.077  1.0
  Mg  Mg2  1  0.989  0.598  0.196  1.0
  Mg  Mg3  1  0.484  0.325  0.487  1.0
  Mg  Mg4  1  0.524  0.587  0.950  1.0
  Mg  Mg5  1  0.896  0.045  0.575  1.0
  Mg  Mg6  1  0.982  0.611  0.720  1.0
  Mg  Mg7  1  0.232  0.100  0.258  1.0
  Si  Si8  1  0.568  0.141  0.884  1.0
  Si  Si9  1  0.240  0.235  0.830  1.0
  Si  Si10  1  0.250  0.691  0.384  1.0
  Si  Si11  1  0.817  0.415  0.466  1.0
  Si  Si12  1  0.651  0.901  0.122  1.0
  Si  Si13  1  0.213  0.865  0.786  1.0
[/CIF]
.
The crystal structure described by Mg4Si3 is alpha Pu-derived structured and crystallizes in the triclinic P1 space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the second Mg site, Mg(2) is bonded in a 4-coordinate geometry to one Si(1), one Si(4), one Si(5), and one Si(6) atom. In the third Mg site, Mg(3) is bonded in a distorted tetrahedral geometry to one Si(2), one Si(3), one Si(4), and one Si(5) atom. In the fourth Mg site, Mg(4) is bonded in a 4-coordinate geometry to one Si(1), one Si(2), one Si(3), one Si(4), and one Si(5) atom. In the fifth Mg site, Mg(5) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the sixth Mg site, Mg(6) is bonded in a 4-coordinate geometry to one Si(1), one Si(3), one Si(4), and one Si(6) atom. In the seventh Mg site, Mg(7) is bonded in a 5-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and one Si(6) atom. In the eighth Mg site, Mg(8) is bonded in a 4-coordinate geometry to one Si(2), one Si(3), one Si(4), one Si(5), and one Si(6) atom. There are six inequivalent Si sites. In the first Si site, Si(1) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(2), one Mg(4), one Mg(5), one Mg(6), one Si(2), and one Si(5) atom. In the second Si site, Si(2) is bonded in a 7-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Mg(7), one Mg(8), one Si(1), and one Si(6) atom. In the third Si site, Si(3) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(7), one Mg(8), and one Si(6) atom. In the fourth Si site, Si(4) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(6), one Mg(7), and one Mg(8) atom. In the fifth Si site, Si(5) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(3), one Mg(4), one Mg(5), one Mg(7), one Mg(8), and one Si(1) atom. In the sixth Si site, Si(6) is bonded in a 8-coordinate geometry to one Mg(1), one Mg(2), one Mg(5), one Mg(6), one Mg(7), one Mg(8), one Si(2), and one Si(3) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.582
_cell_length_b   6.631
_cell_length_c   6.424
_cell_angle_alpha   101.857
_cell_angle_beta   80.218
_cell_angle_gamma   66.535
_symmetry_Int_Tables_number   1
_cell_volume   278.313
_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  0.545  0.831  0.515  1.0
  Mg  Mg1  1  0.859  0.156  0.077  1.0
  Mg  Mg2  1  0.989  0.598  0.196  1.0
  Mg  Mg3  1  0.484  0.325  0.487  1.0
  Mg  Mg4  1  0.524  0.587  0.950  1.0
  Mg  Mg5  1  0.896  0.045  0.575  1.0
  Mg  Mg6  1  0.982  0.611  0.720  1.0
  Mg  Mg7  1  0.232  0.100  0.258  1.0
  Si  Si8  1  0.568  0.141  0.884  1.0
  Si  Si9  1  0.240  0.235  0.830  1.0
  Si  Si10  1  0.250  0.691  0.384  1.0
  Si  Si11  1  0.817  0.415  0.466  1.0
  Si  Si12  1  0.651  0.901  0.122  1.0
  Si  Si13  1  0.213  0.865  0.786  1.0
[/CIF]
.