data_Mg2TiSi
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   2.9
_cell_length_b   2.9
_cell_length_c   8.8
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   92.5
_symmetry_Int_Tables_number   1
_chemical_formula_structural   Mg2TiSi
_chemical_formula_sum   'Mg2 Ti1 Si1'
_cell_volume   73.67
_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  Mg0  1  0.0  0.0  0.71  1.0
  Mg  Mg1  1  0.0  0.0  0.09  1.0
  Ti  Ti3  1  0.0  0.0  0.4  1.0
  Si  Si2  1  0.0  0.0  0.0  1.0

data_Mg2TiSi
_symmetry_space_group_name_H-M   P4mm
_cell_length_a   2.9
_cell_length_b   2.9
_cell_length_c   8.8
_cell_angle_alpha   90.0
_cell_angle_beta   90.0
_cell_angle_gamma   90.0
_symmetry_Int_Tables_number   99
_chemical_formula_structural   Mg2TiSi
_chemical_formula_sum   'Mg2 Ti1 Si1'
_cell_volume   73.74
_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  0.09  1.0
  Mg  Mg1  1  0.0  0.0  0.71  1.0
  Ti  Ti2  1  0.0  0.0  0.4  1.0
  Si  Si3  1  0.0  0.0  0.0  1.0

Mg Mg Ti Si
Mg2TiSi crystallizes in the monoclinic Pm space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to four equivalent Mg(1), one Ti(1), and one Si(1) atom to form distorted MgMg4TiSi octahedra that share corners with four equivalent Mg(1)Mg4TiSi octahedra, edges with four equivalent Mg(1)Mg4TiSi octahedra, and edges with four equivalent Ti(1)Mg2Ti4 octahedra. The corner-sharing octahedra are not tilted. All Mg(1)-Mg(1) bond lengths are 2.90 Å. The Mg(1)-Ti(1) bond length is 2.74 Å. The Mg(1)-Si(1) bond length is 2.56 Å. In the second Mg site, Mg(2) is bonded in a single-bond geometry to one Ti(1) and one Si(1) atom. The Mg(2)-Ti(1) bond length is 2.74 Å. The Mg(2)-Si(1) bond length is 0.76 Å. Ti(1) is bonded to one Mg(1), one Mg(2), and four equivalent Ti(1) atoms to form distorted TiMg2Ti4 octahedra that share corners with four equivalent Ti(1)Mg2Ti4 octahedra, edges with four equivalent Mg(1)Mg4TiSi octahedra, and edges with four equivalent Ti(1)Mg2Ti4 octahedra. The corner-sharing octahedra are not tilted. All Ti(1)-Ti(1) bond lengths are 2.90 Å. Si(1) is bonded in a single-bond geometry to one Mg(1) and one Mg(2) atom.