The material structure described by Mg2SiO4 crystallizes in the triclinic P-1 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), and two equivalent O(8) atoms to form distorted MgO6 octahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with five equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Si(1)O6 octahedra, and edges with two equivalent Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(5), one O(6), and two equivalent O(7) atoms to form distorted MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  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(3)O6 octahedra, and edges with three equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-28°. In the third Mg site, Mg(3) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-18°. In the fourth Mg site, Mg(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form distorted MgO6 octahedra that share corners with three equivalent Mg(2)O6 octahedra, corners with three equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-28°. In the fifth Mg site, Mg(5) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-15°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), one O(7), and two equivalent O(6) atoms to form SiO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Si(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with three equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Si(1)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with five equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-69°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(4), and one Si(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), and one Si(1) atom to form distorted OMg4Si square pyramids that share  a cornercorner with one O(2)Mg4Si square pyramid, corners with three equivalent O(6)Mg3Si2 square pyramids,  a cornercorner with one O(3)Mg2Si2 trigonal pyramid,  a cornercorner with one O(5)Mg3Si trigonal pyramid, edges with three equivalent O(7)Mg5Si octahedra,  an edgeedge with one O(6)Mg3Si2 square pyramid,  an edgeedge with one O(3)Mg2Si2 trigonal pyramid, and  an edgeedge with one O(5)Mg3Si trigonal pyramid. In the third O site, O(3) is bonded to one Mg(1), one Mg(4), one Si(1), and one Si(2) atom to form distorted OMg2Si2 trigonal pyramids that share  a cornercorner with one O(2)Mg4Si square pyramid, corners with two equivalent O(6)Mg3Si2 square pyramids, corners with two equivalent O(5)Mg3Si trigonal pyramids,  an edgeedge with one O(7)Mg5Si octahedra, and  an edgeedge with one O(2)Mg4Si square pyramid. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(4), and one Si(2) atom. In the fifth O site, O(5) is bonded to one Mg(2), one Mg(4), one Mg(5), and one Si(1) atom to form distorted OMg3Si trigonal pyramids that share corners with two equivalent O(7)Mg5Si octahedra,  a cornercorner with one O(6)Mg3Si2 square pyramid,  a cornercorner with one O(2)Mg4Si square pyramid,  a cornercorner with one O(5)Mg3Si trigonal pyramid, corners with two equivalent O(3)Mg2Si2 trigonal pyramids, edges with two equivalent O(7)Mg5Si octahedra,  an edgeedge with one O(2)Mg4Si square pyramid, and edges with two equivalent O(6)Mg3Si2 square pyramids. The corner-sharing octahedral tilt angles range from 4-13°. In the sixth O site, O(6) is bonded to one Mg(2), one Mg(3), one Mg(5), and two equivalent Si(1) atoms to form OMg3Si2 square pyramids that share corners with two equivalent O(6)Mg3Si2 square pyramids, corners with three equivalent O(2)Mg4Si square pyramids,  a cornercorner with one O(5)Mg3Si trigonal pyramid, corners with two equivalent O(3)Mg2Si2 trigonal pyramids, edges with four equivalent O(7)Mg5Si octahedra,  an edgeedge with one O(6)Mg3Si2 square pyramid,  an edgeedge with one O(2)Mg4Si square pyramid, and edges with two equivalent O(5)Mg3Si trigonal pyramids. In the seventh O site, O(7) is bonded to one Mg(3), one Mg(4), one Mg(5), two equivalent Mg(2), and one Si(1) atom to form OMg5Si octahedra that share corners with two equivalent O(7)Mg5Si octahedra, corners with two equivalent O(5)Mg3Si trigonal pyramids,  an edgeedge with one O(7)Mg5Si octahedra, edges with three equivalent O(2)Mg4Si square pyramids, edges with four equivalent O(6)Mg3Si2 square pyramids,  an edgeedge with one O(3)Mg2Si2 trigonal pyramid, and edges with two equivalent O(5)Mg3Si trigonal pyramids. The corner-sharing octahedra are not tilted. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.109
_cell_length_b   5.785
_cell_length_c   10.033
_cell_angle_alpha   92.066
_cell_angle_beta   99.185
_cell_angle_gamma   107.733
_symmetry_Int_Tables_number   1
_cell_volume   277.679
_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  0.522  0.174  0.408  1.0
  Mg  Mg1  1  0.478  0.826  0.592  1.0
  Mg  Mg2  1  0.499  0.115  0.856  1.0
  Mg  Mg3  1  0.000  0.000  0.000  1.0
  Mg  Mg4  1  0.955  0.700  0.722  1.0
  Mg  Mg5  1  0.501  0.885  0.144  1.0
  Mg  Mg6  1  0.045  0.300  0.278  1.0
  Mg  Mg7  1  0.000  0.500  0.000  1.0
  Si  Si8  1  0.508  0.396  0.129  1.0
  Si  Si9  1  0.492  0.604  0.871  1.0
  Si  Si10  1  0.884  0.753  0.394  1.0
  Si  Si11  1  0.116  0.247  0.606  1.0
  O  O12  1  0.230  0.038  0.684  1.0
  O  O13  1  0.705  0.876  0.821  1.0
  O  O14  1  0.748  0.477  0.291  1.0
  O  O15  1  0.240  0.317  0.468  1.0
  O  O16  1  0.770  0.962  0.316  1.0
  O  O17  1  0.295  0.124  0.179  1.0
  O  O18  1  0.252  0.523  0.709  1.0
  O  O19  1  0.713  0.451  0.828  1.0
  O  O20  1  0.710  0.671  0.050  1.0
  O  O21  1  0.760  0.683  0.532  1.0
  O  O22  1  0.290  0.329  0.950  1.0
  O  O23  1  0.734  0.213  0.070  1.0
  O  O24  1  0.223  0.831  0.419  1.0
  O  O25  1  0.266  0.787  0.930  1.0
  O  O26  1  0.287  0.549  0.172  1.0
  O  O27  1  0.777  0.169  0.581  1.0
[/CIF]
.
The material structure described by Mg2SiO4 crystallizes in the triclinic P-1 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), and two equivalent O(8) atoms to form distorted MgO6 octahedra that share  a cornercorner with one Mg(3)O6 octahedra, corners with five equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Si(1)O6 octahedra, and edges with two equivalent Mg(4)O6 octahedra. The corner-sharing octahedral tilt angles are 18°. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), one O(5), one O(6), and two equivalent O(7) atoms to form distorted MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  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(3)O6 octahedra, and edges with three equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-28°. In the third Mg site, Mg(3) is bonded to two equivalent O(2), two equivalent O(6), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-18°. In the fourth Mg site, Mg(4) is bonded to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(7) atom to form distorted MgO6 octahedra that share corners with three equivalent Mg(2)O6 octahedra, corners with three equivalent Si(2)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Mg(5)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 11-28°. In the fifth Mg site, Mg(5) is bonded to two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms to form MgO6 octahedra that share corners with four equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 9-15°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(3), one O(5), one O(7), and two equivalent O(6) atoms to form SiO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(3)O6 octahedra,  an edgeedge with one Si(1)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with three equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 1-12°. In the second Si site, Si(2) is bonded to one O(1), one O(3), one O(4), and one O(8) atom to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Si(1)O6 octahedra, corners with three equivalent Mg(4)O6 octahedra, and corners with five equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 49-69°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(4), and one Si(2) atom. In the second O site, O(2) is bonded to one Mg(1), one Mg(2), one Mg(3), one Mg(4), and one Si(1) atom to form distorted OMg4Si square pyramids that share  a cornercorner with one O(2)Mg4Si square pyramid, corners with three equivalent O(6)Mg3Si2 square pyramids,  a cornercorner with one O(3)Mg2Si2 trigonal pyramid,  a cornercorner with one O(5)Mg3Si trigonal pyramid, edges with three equivalent O(7)Mg5Si octahedra,  an edgeedge with one O(6)Mg3Si2 square pyramid,  an edgeedge with one O(3)Mg2Si2 trigonal pyramid, and  an edgeedge with one O(5)Mg3Si trigonal pyramid. In the third O site, O(3) is bonded to one Mg(1), one Mg(4), one Si(1), and one Si(2) atom to form distorted OMg2Si2 trigonal pyramids that share  a cornercorner with one O(2)Mg4Si square pyramid, corners with two equivalent O(6)Mg3Si2 square pyramids, corners with two equivalent O(5)Mg3Si trigonal pyramids,  an edgeedge with one O(7)Mg5Si octahedra, and  an edgeedge with one O(2)Mg4Si square pyramid. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Mg(1), one Mg(4), and one Si(2) atom. In the fifth O site, O(5) is bonded to one Mg(2), one Mg(4), one Mg(5), and one Si(1) atom to form distorted OMg3Si trigonal pyramids that share corners with two equivalent O(7)Mg5Si octahedra,  a cornercorner with one O(6)Mg3Si2 square pyramid,  a cornercorner with one O(2)Mg4Si square pyramid,  a cornercorner with one O(5)Mg3Si trigonal pyramid, corners with two equivalent O(3)Mg2Si2 trigonal pyramids, edges with two equivalent O(7)Mg5Si octahedra,  an edgeedge with one O(2)Mg4Si square pyramid, and edges with two equivalent O(6)Mg3Si2 square pyramids. The corner-sharing octahedral tilt angles range from 4-13°. In the sixth O site, O(6) is bonded to one Mg(2), one Mg(3), one Mg(5), and two equivalent Si(1) atoms to form OMg3Si2 square pyramids that share corners with two equivalent O(6)Mg3Si2 square pyramids, corners with three equivalent O(2)Mg4Si square pyramids,  a cornercorner with one O(5)Mg3Si trigonal pyramid, corners with two equivalent O(3)Mg2Si2 trigonal pyramids, edges with four equivalent O(7)Mg5Si octahedra,  an edgeedge with one O(6)Mg3Si2 square pyramid,  an edgeedge with one O(2)Mg4Si square pyramid, and edges with two equivalent O(5)Mg3Si trigonal pyramids. In the seventh O site, O(7) is bonded to one Mg(3), one Mg(4), one Mg(5), two equivalent Mg(2), and one Si(1) atom to form OMg5Si octahedra that share corners with two equivalent O(7)Mg5Si octahedra, corners with two equivalent O(5)Mg3Si trigonal pyramids,  an edgeedge with one O(7)Mg5Si octahedra, edges with three equivalent O(2)Mg4Si square pyramids, edges with four equivalent O(6)Mg3Si2 square pyramids,  an edgeedge with one O(3)Mg2Si2 trigonal pyramid, and edges with two equivalent O(5)Mg3Si trigonal pyramids. The corner-sharing octahedra are not tilted. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to two equivalent Mg(1) and one Si(2) atom. is represented by the CIF file [CIF]
data_Mg2SiO4
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.109
_cell_length_b   5.785
_cell_length_c   10.033
_cell_angle_alpha   92.066
_cell_angle_beta   99.185
_cell_angle_gamma   107.733
_symmetry_Int_Tables_number   1
_cell_volume   277.679
_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  0.522  0.174  0.408  1.0
  Mg  Mg1  1  0.478  0.826  0.592  1.0
  Mg  Mg2  1  0.499  0.115  0.856  1.0
  Mg  Mg3  1  0.000  0.000  0.000  1.0
  Mg  Mg4  1  0.955  0.700  0.722  1.0
  Mg  Mg5  1  0.501  0.885  0.144  1.0
  Mg  Mg6  1  0.045  0.300  0.278  1.0
  Mg  Mg7  1  0.000  0.500  0.000  1.0
  Si  Si8  1  0.508  0.396  0.129  1.0
  Si  Si9  1  0.492  0.604  0.871  1.0
  Si  Si10  1  0.884  0.753  0.394  1.0
  Si  Si11  1  0.116  0.247  0.606  1.0
  O  O12  1  0.230  0.038  0.684  1.0
  O  O13  1  0.705  0.876  0.821  1.0
  O  O14  1  0.748  0.477  0.291  1.0
  O  O15  1  0.240  0.317  0.468  1.0
  O  O16  1  0.770  0.962  0.316  1.0
  O  O17  1  0.295  0.124  0.179  1.0
  O  O18  1  0.252  0.523  0.709  1.0
  O  O19  1  0.713  0.451  0.828  1.0
  O  O20  1  0.710  0.671  0.050  1.0
  O  O21  1  0.760  0.683  0.532  1.0
  O  O22  1  0.290  0.329  0.950  1.0
  O  O23  1  0.734  0.213  0.070  1.0
  O  O24  1  0.223  0.831  0.419  1.0
  O  O25  1  0.266  0.787  0.930  1.0
  O  O26  1  0.287  0.549  0.172  1.0
  O  O27  1  0.777  0.169  0.581  1.0
[/CIF]
.