The compound described by Mg2SiO4 is Spinel-like structured and crystallizes in the trigonal P-3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the second Mg site, Mg(2) is bonded to six equivalent O(2) atoms to form MgO6 octahedra that share corners with twelve equivalent Mg(1)O6 octahedra and corners with six equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. Si(1) is bonded to one O(1) and three equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and edges with three equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-57°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Mg(1) and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.015
_cell_length_b   6.015
_cell_length_c   4.829
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   151.281
_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  0.500  0.000  0.500  1.0
  Mg  Mg1  1  0.000  0.500  0.500  1.0
  Mg  Mg2  1  0.000  0.000  0.000  1.0
  Mg  Mg3  1  0.500  0.500  0.500  1.0
  Si  Si4  1  0.333  0.667  0.927  1.0
  Si  Si5  1  0.667  0.333  0.073  1.0
  O  O6  1  0.333  0.667  0.265  1.0
  O  O7  1  0.811  0.189  0.223  1.0
  O  O8  1  0.667  0.333  0.735  1.0
  O  O9  1  0.811  0.623  0.223  1.0
  O  O10  1  0.377  0.189  0.223  1.0
  O  O11  1  0.189  0.811  0.777  1.0
  O  O12  1  0.189  0.377  0.777  1.0
  O  O13  1  0.623  0.811  0.777  1.0
[/CIF]
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The compound described by Mg2SiO4 is Spinel-like structured and crystallizes in the trigonal P-3m1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, edges with four equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. In the second Mg site, Mg(2) is bonded to six equivalent O(2) atoms to form MgO6 octahedra that share corners with twelve equivalent Mg(1)O6 octahedra and corners with six equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 55°. Si(1) is bonded to one O(1) and three equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, and edges with three equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 54-57°. There are two inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to three equivalent Mg(1) and one Si(1) atom. In the second O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(2), two equivalent Mg(1), and one Si(1) atom. is represented by the Crystallographic Information File (CIF) [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.015
_cell_length_b   6.015
_cell_length_c   4.829
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   120.000
_symmetry_Int_Tables_number   1
_cell_volume   151.281
_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  0.500  0.000  0.500  1.0
  Mg  Mg1  1  0.000  0.500  0.500  1.0
  Mg  Mg2  1  0.000  0.000  0.000  1.0
  Mg  Mg3  1  0.500  0.500  0.500  1.0
  Si  Si4  1  0.333  0.667  0.927  1.0
  Si  Si5  1  0.667  0.333  0.073  1.0
  O  O6  1  0.333  0.667  0.265  1.0
  O  O7  1  0.811  0.189  0.223  1.0
  O  O8  1  0.667  0.333  0.735  1.0
  O  O9  1  0.811  0.623  0.223  1.0
  O  O10  1  0.377  0.189  0.223  1.0
  O  O11  1  0.189  0.811  0.777  1.0
  O  O12  1  0.189  0.377  0.777  1.0
  O  O13  1  0.623  0.811  0.777  1.0
[/CIF]
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