data_MgFe2Si
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   3.0
_cell_length_b   3.0
_cell_length_c   5.99
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   1
_chemical_formula_structural   MgFe2Si
_chemical_formula_sum   'Mg1 Fe2 Si1'
_cell_volume   54.0
_cell_formula_units_Z   1
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  Mg2  1  0.0  0.0  0.94  1.0
  Fe  Fe0  1  0.0  0.0  0.95  1.0
  Fe  Fe1  1  0.5  0.5  0.27  1.0
  Si  Si3  1  0.5  0.5  0.8  1.0

data_MgFe2Si
_symmetry_space_group_name_H-M   P4mm
_cell_length_a   3.0
_cell_length_b   3.0
_cell_length_c   5.99
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   99
_chemical_formula_structural   MgFe2Si
_chemical_formula_sum   'Mg1 Fe2 Si1'
_cell_volume   54.0
_cell_formula_units_Z   1
loop_
 _symmetry_equiv_pos_site_id
 _symmetry_equiv_pos_as_xyz
  1  'x, y, z'
  2  '-y, x, z'
  3  '-x, -y, z'
  4  'y, -x, z'
  5  '-x, y, z'
  6  'y, x, z'
  7  'x, -y, z'
  8  '-y, -x, 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  0.0  0.0  0.94  1.0
  Fe  Fe1  1  0.0  0.0  0.95  1.0
  Fe  Fe2  1  0.5  0.5  0.27  1.0
  Si  Si3  1  0.5  0.5  0.8  1.0

Mg Fe Fe Si
Mg Fe Fe Si 0 1 o o o 0 2 o o + 0 2 o - + 0 2 - o + 0 2 - - + 0 3 o o o 0 3 o - o 0 3 - o o 0 3 - - o 1 2 o o + 1 2 o - + 1 2 - o + 1 2 - - + 1 3 o o o 1 3 o - o 1 3 - o o 1 3 - - o 2 2 + o o 2 2 o + o 2 3 o o - 2 3 o o o 
MgFe2Si crystallizes in the monoclinic Cm space group. Mg(1) is bonded in a single-bond geometry to one Fe(1) and four equivalent Si(1) atoms. The Mg(1)-Fe(1) bond length is 0.09 Å. There is one shorter (2.27 Å) and three longer (2.28 Å) Mg(1)-Si(1) bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a single-bond geometry to one Mg(1) and four equivalent Fe(2) atoms. There is one shorter (2.85 Å) and three longer (2.86 Å) Fe(1)-Fe(2) bond lengths. In the second Fe site, Fe(2) is bonded in a 10-coordinate geometry to four equivalent Fe(1), four equivalent Fe(2), and two equivalent Si(1) atoms. All Fe(2)-Fe(2) bond lengths are 3.00 Å. There is one shorter (2.82 Å) and one longer (3.17 Å) Fe(2)-Si(1) bond length. Si(1) is bonded in a 4-coordinate geometry to four equivalent Mg(1) and two equivalent Fe(2) atoms.