The material structure described by Mg4Si3 crystallizes in the orthorhombic I222 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(2) and four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(1), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), one Si(2), and two equivalent Si(1) atoms. is represented by the CIF card [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.660
_cell_length_b   7.660
_cell_length_c   7.660
_cell_angle_alpha   134.245
_cell_angle_beta   122.470
_cell_angle_gamma   76.433
_symmetry_Int_Tables_number   1
_cell_volume   264.250
_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  0.250  0.661  0.090  1.0
  Mg  Mg1  1  0.790  0.790  0.000  1.0
  Mg  Mg2  1  0.197  0.697  0.500  1.0
  Mg  Mg3  1  0.210  0.210  0.000  1.0
  Mg  Mg4  1  0.429  0.339  0.589  1.0
  Mg  Mg5  1  0.571  0.160  0.910  1.0
  Mg  Mg6  1  0.750  0.840  0.411  1.0
  Mg  Mg7  1  0.803  0.303  0.500  1.0
  Si  Si8  1  0.438  0.892  0.052  1.0
  Si  Si9  1  0.161  0.108  0.546  1.0
  Si  Si10  1  0.000  0.209  0.209  1.0
  Si  Si11  1  0.839  0.385  0.948  1.0
  Si  Si12  1  0.562  0.615  0.454  1.0
  Si  Si13  1  0.000  0.791  0.791  1.0
[/CIF]
.
The material structure described by Mg4Si3 crystallizes in the orthorhombic I222 space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 5-coordinate geometry to one Si(2) and four equivalent Si(1) atoms. In the second Mg site, Mg(2) is bonded in a 6-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. In the third Mg site, Mg(3) is bonded in a 6-coordinate geometry to two equivalent Si(2) and four equivalent Si(1) atoms. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to two equivalent Mg(2), two equivalent Mg(3), four equivalent Mg(1), and one Si(2) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to two equivalent Mg(1), two equivalent Mg(2), two equivalent Mg(3), one Si(2), and two equivalent Si(1) atoms. is represented by the CIF card [CIF]
data_Mg4Si3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   7.660
_cell_length_b   7.660
_cell_length_c   7.660
_cell_angle_alpha   134.245
_cell_angle_beta   122.470
_cell_angle_gamma   76.433
_symmetry_Int_Tables_number   1
_cell_volume   264.250
_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  0.250  0.661  0.090  1.0
  Mg  Mg1  1  0.790  0.790  0.000  1.0
  Mg  Mg2  1  0.197  0.697  0.500  1.0
  Mg  Mg3  1  0.210  0.210  0.000  1.0
  Mg  Mg4  1  0.429  0.339  0.589  1.0
  Mg  Mg5  1  0.571  0.160  0.910  1.0
  Mg  Mg6  1  0.750  0.840  0.411  1.0
  Mg  Mg7  1  0.803  0.303  0.500  1.0
  Si  Si8  1  0.438  0.892  0.052  1.0
  Si  Si9  1  0.161  0.108  0.546  1.0
  Si  Si10  1  0.000  0.209  0.209  1.0
  Si  Si11  1  0.839  0.385  0.948  1.0
  Si  Si12  1  0.562  0.615  0.454  1.0
  Si  Si13  1  0.000  0.791  0.791  1.0
[/CIF]
.