The material structure described by Mg2SiO4 crystallizes in the orthorhombic Imma space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with three equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-61°. There are four inequivalent O sites. In the first O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(3), and one Si(1) atom. In the second O site, O(3) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form edge-sharing OMg5 square pyramids. In the third O site, O(4) is bonded in a trigonal planar geometry to one Mg(2) and two equivalent Si(1) atoms. In the fourth O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(3), 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   7.693
_cell_length_b   7.693
_cell_length_c   7.693
_cell_angle_alpha   135.998
_cell_angle_beta   114.204
_cell_angle_gamma   82.570
_symmetry_Int_Tables_number   1
_cell_volume   278.400
_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  0.500  0.500  0.000  1.0
  Mg  Mg1  1  0.000  0.000  0.000  1.0
  Mg  Mg2  1  0.280  0.250  0.030  1.0
  Mg  Mg3  1  0.720  0.750  0.970  1.0
  Mg  Mg4  1  0.122  0.122  0.500  1.0
  Mg  Mg5  1  0.878  0.378  0.000  1.0
  Mg  Mg6  1  0.878  0.878  0.500  1.0
  Mg  Mg7  1  0.122  0.622  0.000  1.0
  Si  Si8  1  0.764  0.380  0.384  1.0
  Si  Si9  1  0.236  0.620  0.616  1.0
  Si  Si10  1  0.503  0.120  0.384  1.0
  Si  Si11  1  0.497  0.880  0.616  1.0
  O  O12  1  0.130  0.384  0.269  1.0
  O  O13  1  0.870  0.139  0.254  1.0
  O  O14  1  0.385  0.116  0.746  1.0
  O  O15  1  0.615  0.361  0.731  1.0
  O  O16  1  0.870  0.616  0.731  1.0
  O  O17  1  0.130  0.861  0.746  1.0
  O  O18  1  0.615  0.884  0.254  1.0
  O  O19  1  0.385  0.639  0.269  1.0
  O  O20  1  0.266  0.010  0.256  1.0
  O  O21  1  0.734  0.990  0.744  1.0
  O  O22  1  0.745  0.490  0.256  1.0
  O  O23  1  0.255  0.510  0.744  1.0
  O  O24  1  0.034  0.250  0.784  1.0
  O  O25  1  0.966  0.750  0.216  1.0
  O  O26  1  0.534  0.250  0.284  1.0
  O  O27  1  0.466  0.750  0.716  1.0
[/CIF]
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The material structure described by Mg2SiO4 crystallizes in the orthorhombic Imma space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with three equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-61°. There are four inequivalent O sites. In the first O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(3), and one Si(1) atom. In the second O site, O(3) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form edge-sharing OMg5 square pyramids. In the third O site, O(4) is bonded in a trigonal planar geometry to one Mg(2) and two equivalent Si(1) atoms. In the fourth O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(3), 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   7.693
_cell_length_b   7.693
_cell_length_c   7.693
_cell_angle_alpha   135.998
_cell_angle_beta   114.204
_cell_angle_gamma   82.570
_symmetry_Int_Tables_number   1
_cell_volume   278.400
_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  0.500  0.500  0.000  1.0
  Mg  Mg1  1  0.000  0.000  0.000  1.0
  Mg  Mg2  1  0.280  0.250  0.030  1.0
  Mg  Mg3  1  0.720  0.750  0.970  1.0
  Mg  Mg4  1  0.122  0.122  0.500  1.0
  Mg  Mg5  1  0.878  0.378  0.000  1.0
  Mg  Mg6  1  0.878  0.878  0.500  1.0
  Mg  Mg7  1  0.122  0.622  0.000  1.0
  Si  Si8  1  0.764  0.380  0.384  1.0
  Si  Si9  1  0.236  0.620  0.616  1.0
  Si  Si10  1  0.503  0.120  0.384  1.0
  Si  Si11  1  0.497  0.880  0.616  1.0
  O  O12  1  0.130  0.384  0.269  1.0
  O  O13  1  0.870  0.139  0.254  1.0
  O  O14  1  0.385  0.116  0.746  1.0
  O  O15  1  0.615  0.361  0.731  1.0
  O  O16  1  0.870  0.616  0.731  1.0
  O  O17  1  0.130  0.861  0.746  1.0
  O  O18  1  0.615  0.884  0.254  1.0
  O  O19  1  0.385  0.639  0.269  1.0
  O  O20  1  0.266  0.010  0.256  1.0
  O  O21  1  0.734  0.990  0.744  1.0
  O  O22  1  0.745  0.490  0.256  1.0
  O  O23  1  0.255  0.510  0.744  1.0
  O  O24  1  0.034  0.250  0.784  1.0
  O  O25  1  0.966  0.750  0.216  1.0
  O  O26  1  0.534  0.250  0.284  1.0
  O  O27  1  0.466  0.750  0.716  1.0
[/CIF]
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