The compound described by MgSiO3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(4), one O(6), and two equivalent O(1) atoms to form MgO4 trigonal pyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Si(1)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Mg(1)O4 trigonal pyramids, and edges with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-63°. In the second Mg site, Mg(2) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with two equivalent Si(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with two equivalent Mg(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 28-43°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form distorted SiO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with three equivalent Si(2)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent Mg(2)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-43°. In the second Si site, Si(2) is bonded to one O(2), one O(5), and two equivalent O(4) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with three equivalent Si(1)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Mg(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 36-71°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Mg(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Mg(2) and two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Si(2) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Mg(1), one Mg(2), and one Si(1) atom. is represented by the CIF file [CIF]
data_MgSiO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.095
_cell_length_b   8.534
_cell_length_c   9.562
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   415.785
_cell_formula_units_Z   8
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  0.929  0.882  0.711  1.0
  Mg  Mg1  1  0.837  0.644  0.516  1.0
  Mg  Mg2  1  0.071  0.118  0.211  1.0
  Mg  Mg3  1  0.571  0.382  0.211  1.0
  Mg  Mg4  1  0.163  0.356  0.016  1.0
  Mg  Mg5  1  0.663  0.144  0.016  1.0
  Mg  Mg6  1  0.429  0.618  0.711  1.0
  Mg  Mg7  1  0.337  0.856  0.516  1.0
  Si  Si8  1  0.810  0.341  0.753  1.0
  Si  Si9  1  0.690  0.841  0.253  1.0
  Si  Si10  1  0.310  0.159  0.753  1.0
  Si  Si11  1  0.190  0.659  0.253  1.0
  Si  Si12  1  0.656  0.153  0.469  1.0
  Si  Si13  1  0.844  0.653  0.969  1.0
  Si  Si14  1  0.156  0.347  0.469  1.0
  Si  Si15  1  0.344  0.847  0.969  1.0
  O  O16  1  0.370  0.207  0.128  1.0
  O  O17  1  0.074  0.507  0.386  1.0
  O  O18  1  0.926  0.493  0.886  1.0
  O  O19  1  0.130  0.707  0.628  1.0
  O  O20  1  0.988  0.794  0.344  1.0
  O  O21  1  0.630  0.793  0.628  1.0
  O  O22  1  0.574  0.993  0.386  1.0
  O  O23  1  0.488  0.706  0.344  1.0
  O  O24  1  0.453  0.296  0.412  1.0
  O  O25  1  0.848  0.658  0.141  1.0
  O  O26  1  0.047  0.796  0.912  1.0
  O  O27  1  0.012  0.206  0.844  1.0
  O  O28  1  0.953  0.204  0.412  1.0
  O  O29  1  0.547  0.704  0.912  1.0
  O  O30  1  0.191  0.033  0.640  1.0
  O  O31  1  0.348  0.842  0.141  1.0
  O  O32  1  0.870  0.293  0.128  1.0
  O  O33  1  0.426  0.007  0.886  1.0
  O  O34  1  0.809  0.967  0.140  1.0
  O  O35  1  0.652  0.158  0.641  1.0
  O  O36  1  0.512  0.294  0.844  1.0
  O  O37  1  0.309  0.533  0.140  1.0
  O  O38  1  0.152  0.342  0.641  1.0
  O  O39  1  0.691  0.467  0.640  1.0
[/CIF]
.
The compound described by MgSiO3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to one O(4), one O(6), and two equivalent O(1) atoms to form MgO4 trigonal pyramids that share  a cornercorner with one Mg(2)O6 octahedra,  a cornercorner with one Si(1)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, corners with two equivalent Mg(1)O4 trigonal pyramids, and edges with two equivalent Mg(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 41-63°. In the second Mg site, Mg(2) is bonded to one O(2), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with two equivalent Si(1)O6 octahedra,  a cornercorner with one Si(2)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Si(1)O6 octahedra, and edges with two equivalent Mg(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 28-43°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(6), two equivalent O(3), and two equivalent O(5) atoms to form distorted SiO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with three equivalent Si(2)O4 tetrahedra,  a cornercorner with one Mg(1)O4 trigonal pyramid, edges with two equivalent Mg(2)O6 octahedra, and edges with two equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 28-43°. In the second Si site, Si(2) is bonded to one O(2), one O(5), and two equivalent O(4) atoms to form SiO4 tetrahedra that share  a cornercorner with one Mg(2)O6 octahedra, corners with three equivalent Si(1)O6 octahedra, corners with two equivalent Si(2)O4 tetrahedra, and corners with two equivalent Mg(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles range from 36-71°. There are six inequivalent O sites. In the first O site, O(1) is bonded in a rectangular see-saw-like geometry to two equivalent Mg(1) and two equivalent Mg(2) atoms. In the second O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Si(1), and one Si(2) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent Mg(2) and two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1) and two equivalent Si(2) atoms. In the fifth O site, O(5) is bonded in a 3-coordinate geometry to one Si(2) and two equivalent Si(1) atoms. In the sixth O site, O(6) is bonded in a distorted T-shaped geometry to one Mg(1), one Mg(2), and one Si(1) atom. is represented by the CIF file [CIF]
data_MgSiO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   5.095
_cell_length_b   8.534
_cell_length_c   9.562
_cell_angle_alpha   90.000
_cell_angle_beta   90.000
_cell_angle_gamma   90.000
_symmetry_Int_Tables_number   1
_cell_volume   415.785
_cell_formula_units_Z   8
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  0.929  0.882  0.711  1.0
  Mg  Mg1  1  0.837  0.644  0.516  1.0
  Mg  Mg2  1  0.071  0.118  0.211  1.0
  Mg  Mg3  1  0.571  0.382  0.211  1.0
  Mg  Mg4  1  0.163  0.356  0.016  1.0
  Mg  Mg5  1  0.663  0.144  0.016  1.0
  Mg  Mg6  1  0.429  0.618  0.711  1.0
  Mg  Mg7  1  0.337  0.856  0.516  1.0
  Si  Si8  1  0.810  0.341  0.753  1.0
  Si  Si9  1  0.690  0.841  0.253  1.0
  Si  Si10  1  0.310  0.159  0.753  1.0
  Si  Si11  1  0.190  0.659  0.253  1.0
  Si  Si12  1  0.656  0.153  0.469  1.0
  Si  Si13  1  0.844  0.653  0.969  1.0
  Si  Si14  1  0.156  0.347  0.469  1.0
  Si  Si15  1  0.344  0.847  0.969  1.0
  O  O16  1  0.370  0.207  0.128  1.0
  O  O17  1  0.074  0.507  0.386  1.0
  O  O18  1  0.926  0.493  0.886  1.0
  O  O19  1  0.130  0.707  0.628  1.0
  O  O20  1  0.988  0.794  0.344  1.0
  O  O21  1  0.630  0.793  0.628  1.0
  O  O22  1  0.574  0.993  0.386  1.0
  O  O23  1  0.488  0.706  0.344  1.0
  O  O24  1  0.453  0.296  0.412  1.0
  O  O25  1  0.848  0.658  0.141  1.0
  O  O26  1  0.047  0.796  0.912  1.0
  O  O27  1  0.012  0.206  0.844  1.0
  O  O28  1  0.953  0.204  0.412  1.0
  O  O29  1  0.547  0.704  0.912  1.0
  O  O30  1  0.191  0.033  0.640  1.0
  O  O31  1  0.348  0.842  0.141  1.0
  O  O32  1  0.870  0.293  0.128  1.0
  O  O33  1  0.426  0.007  0.886  1.0
  O  O34  1  0.809  0.967  0.140  1.0
  O  O35  1  0.652  0.158  0.641  1.0
  O  O36  1  0.512  0.294  0.844  1.0
  O  O37  1  0.309  0.533  0.140  1.0
  O  O38  1  0.152  0.342  0.641  1.0
  O  O39  1  0.691  0.467  0.640  1.0
[/CIF]
.