The structure described by Mg2SiO4 is Spinel-like structured and crystallizes in the orthorhombic Imma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form MgO4 tetrahedra that share corners with six equivalent Mg(2)O6 octahedra and corners with six equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-66°. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. Si(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SiO6 octahedra that share corners with six equivalent Mg(1)O4 tetrahedra, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. There are two 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(2), and two equivalent Si(1) atoms. In the second O site, O(2) is bonded to one Mg(1), two equivalent Mg(2), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OMg3Si tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.833
_cell_length_b   5.833
_cell_length_c   5.833
_cell_angle_alpha   121.247
_cell_angle_beta   119.765
_cell_angle_gamma   89.131
_symmetry_Int_Tables_number   1
_cell_volume   139.178
_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  0.859  0.109  0.750  1.0
  Mg  Mg1  1  0.500  0.500  0.000  1.0
  Mg  Mg2  1  0.000  0.500  0.500  1.0
  Mg  Mg3  1  0.141  0.891  0.250  1.0
  Si  Si4  1  0.500  0.500  0.500  1.0
  Si  Si5  1  0.500  0.000  0.000  1.0
  O  O6  1  0.285  0.249  0.036  1.0
  O  O7  1  0.710  0.221  0.011  1.0
  O  O8  1  0.713  0.249  0.464  1.0
  O  O9  1  0.710  0.699  0.489  1.0
  O  O10  1  0.290  0.301  0.511  1.0
  O  O11  1  0.287  0.751  0.536  1.0
  O  O12  1  0.290  0.779  0.989  1.0
  O  O13  1  0.715  0.751  0.964  1.0
[/CIF]
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The structure described by Mg2SiO4 is Spinel-like structured and crystallizes in the orthorhombic Imma space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and two equivalent O(2) atoms to form MgO4 tetrahedra that share corners with six equivalent Mg(2)O6 octahedra and corners with six equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 52-66°. In the second Mg site, Mg(2) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with six equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. Si(1) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form SiO6 octahedra that share corners with six equivalent Mg(1)O4 tetrahedra, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. There are two 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(2), and two equivalent Si(1) atoms. In the second O site, O(2) is bonded to one Mg(1), two equivalent Mg(2), and one Si(1) atom to form a mixture of distorted corner and edge-sharing OMg3Si tetrahedra. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.833
_cell_length_b   5.833
_cell_length_c   5.833
_cell_angle_alpha   121.247
_cell_angle_beta   119.765
_cell_angle_gamma   89.131
_symmetry_Int_Tables_number   1
_cell_volume   139.178
_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  0.859  0.109  0.750  1.0
  Mg  Mg1  1  0.500  0.500  0.000  1.0
  Mg  Mg2  1  0.000  0.500  0.500  1.0
  Mg  Mg3  1  0.141  0.891  0.250  1.0
  Si  Si4  1  0.500  0.500  0.500  1.0
  Si  Si5  1  0.500  0.000  0.000  1.0
  O  O6  1  0.285  0.249  0.036  1.0
  O  O7  1  0.710  0.221  0.011  1.0
  O  O8  1  0.713  0.249  0.464  1.0
  O  O9  1  0.710  0.699  0.489  1.0
  O  O10  1  0.290  0.301  0.511  1.0
  O  O11  1  0.287  0.751  0.536  1.0
  O  O12  1  0.290  0.779  0.989  1.0
  O  O13  1  0.715  0.751  0.964  1.0
[/CIF]
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