The structure described by Mg2SiO4 is Ilmenite-like structured and crystallizes in the monoclinic P2/m space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-57°. In the second Mg site, Mg(2) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent Mg(3)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the third Mg site, Mg(3) is bonded to two equivalent O(6) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with eight equivalent Mg(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with four equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-57°. In the fourth Mg site, Mg(4) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. In the fifth Mg site, Mg(5) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(4)O6 octahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(6), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra,  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(4)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-55°. In the second Si site, Si(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Mg(4)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(4), one Mg(5), and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(5), two equivalent Mg(1), and one Si(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(4), two equivalent Mg(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(3), and one Si(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(3), two equivalent Mg(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.081
_cell_length_b   4.800
_cell_length_c   10.481
_cell_angle_alpha   89.919
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   305.937
_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  0.743  0.497  0.742  1.0
  Mg  Mg1  1  0.257  0.503  0.258  1.0
  Mg  Mg2  1  0.000  0.500  0.500  1.0
  Mg  Mg3  1  0.257  0.497  0.742  1.0
  Mg  Mg4  1  0.743  0.503  0.258  1.0
  Mg  Mg5  1  0.500  0.000  0.500  1.0
  Mg  Mg6  1  0.000  0.500  0.000  1.0
  Mg  Mg7  1  0.500  0.500  0.000  1.0
  Si  Si8  1  0.500  0.093  0.165  1.0
  Si  Si9  1  0.500  0.907  0.835  1.0
  Si  Si10  1  0.000  0.918  0.331  1.0
  Si  Si11  1  0.000  0.082  0.669  1.0
  O  O12  1  0.285  0.742  0.903  1.0
  O  O13  1  0.500  0.755  0.166  1.0
  O  O14  1  0.715  0.742  0.903  1.0
  O  O15  1  0.000  0.744  0.191  1.0
  O  O16  1  0.715  0.258  0.097  1.0
  O  O17  1  0.784  0.775  0.407  1.0
  O  O18  1  0.285  0.258  0.097  1.0
  O  O19  1  0.216  0.775  0.407  1.0
  O  O20  1  0.784  0.225  0.593  1.0
  O  O21  1  0.000  0.257  0.333  1.0
  O  O22  1  0.500  0.772  0.687  1.0
  O  O23  1  0.000  0.743  0.667  1.0
  O  O24  1  0.500  0.245  0.834  1.0
  O  O25  1  0.500  0.228  0.313  1.0
  O  O26  1  0.000  0.256  0.809  1.0
  O  O27  1  0.216  0.225  0.593  1.0
[/CIF]
.
The structure described by Mg2SiO4 is Ilmenite-like structured and crystallizes in the monoclinic P2/m space group. There are five inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra,  a cornercorner with one Si(1)O4 tetrahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(4)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra,  an edgeedge with one Si(1)O4 tetrahedra, and  an edgeedge with one Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 56-57°. In the second Mg site, Mg(2) is bonded to two equivalent O(5) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent Mg(3)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the third Mg site, Mg(3) is bonded to two equivalent O(6) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with eight equivalent Mg(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with four equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 55-57°. In the fourth Mg site, Mg(4) is bonded to two equivalent O(3) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with two equivalent Si(2)O4 tetrahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with four equivalent Mg(1)O6 octahedra. In the fifth Mg site, Mg(5) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with two equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(4)O6 octahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(6), and two equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mg(3)O6 octahedra,  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(4)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 2-55°. In the second Si site, Si(2) is bonded to one O(3), one O(5), and two equivalent O(4) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Mg(4)O6 octahedra, corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Mg(3)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra, and edges with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-56°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(4), one Mg(5), and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(5), two equivalent Mg(1), and one Si(1) atom. In the third O site, O(3) is bonded in a rectangular see-saw-like geometry to one Mg(4), two equivalent Mg(1), and one Si(2) atom. In the fourth O site, O(4) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(3), and one Si(2) atom. In the fifth O site, O(5) is bonded in a rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a rectangular see-saw-like geometry to one Mg(3), two equivalent Mg(1), and one Si(1) atom. is represented by the CIF file [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.081
_cell_length_b   4.800
_cell_length_c   10.481
_cell_angle_alpha   89.919
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   305.937
_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  0.743  0.497  0.742  1.0
  Mg  Mg1  1  0.257  0.503  0.258  1.0
  Mg  Mg2  1  0.000  0.500  0.500  1.0
  Mg  Mg3  1  0.257  0.497  0.742  1.0
  Mg  Mg4  1  0.743  0.503  0.258  1.0
  Mg  Mg5  1  0.500  0.000  0.500  1.0
  Mg  Mg6  1  0.000  0.500  0.000  1.0
  Mg  Mg7  1  0.500  0.500  0.000  1.0
  Si  Si8  1  0.500  0.093  0.165  1.0
  Si  Si9  1  0.500  0.907  0.835  1.0
  Si  Si10  1  0.000  0.918  0.331  1.0
  Si  Si11  1  0.000  0.082  0.669  1.0
  O  O12  1  0.285  0.742  0.903  1.0
  O  O13  1  0.500  0.755  0.166  1.0
  O  O14  1  0.715  0.742  0.903  1.0
  O  O15  1  0.000  0.744  0.191  1.0
  O  O16  1  0.715  0.258  0.097  1.0
  O  O17  1  0.784  0.775  0.407  1.0
  O  O18  1  0.285  0.258  0.097  1.0
  O  O19  1  0.216  0.775  0.407  1.0
  O  O20  1  0.784  0.225  0.593  1.0
  O  O21  1  0.000  0.257  0.333  1.0
  O  O22  1  0.500  0.772  0.687  1.0
  O  O23  1  0.000  0.743  0.667  1.0
  O  O24  1  0.500  0.245  0.834  1.0
  O  O25  1  0.500  0.228  0.313  1.0
  O  O26  1  0.000  0.256  0.809  1.0
  O  O27  1  0.216  0.225  0.593  1.0
[/CIF]
.