The compound described by MgSiO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra, edges with three equivalent Mg(2)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(3) 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 three equivalent Mg(1)O6 octahedra. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-61°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Mg(1), one Mg(2), and one Si(1) atom. In the third O site, O(3) is bonded to one Mg(1), two equivalent Mg(2), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSiO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.660
_cell_length_b   6.660
_cell_length_c   5.307
_cell_angle_alpha   73.138
_cell_angle_beta   73.138
_cell_angle_gamma   81.757
_symmetry_Int_Tables_number   1
_cell_volume   215.117
_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  0.262  0.738  0.250  1.0
  Mg  Mg1  1  0.902  0.098  0.250  1.0
  Mg  Mg2  1  0.738  0.262  0.750  1.0
  Mg  Mg3  1  0.098  0.902  0.750  1.0
  Si  Si4  1  0.618  0.798  0.797  1.0
  Si  Si5  1  0.202  0.382  0.703  1.0
  Si  Si6  1  0.798  0.618  0.297  1.0
  Si  Si7  1  0.382  0.202  0.203  1.0
  O  O8  1  0.682  0.621  0.620  1.0
  O  O9  1  0.621  0.682  0.120  1.0
  O  O10  1  0.869  0.375  0.342  1.0
  O  O11  1  0.625  0.131  0.158  1.0
  O  O12  1  0.318  0.379  0.380  1.0
  O  O13  1  0.789  0.974  0.665  1.0
  O  O14  1  0.379  0.318  0.880  1.0
  O  O15  1  0.211  0.026  0.335  1.0
  O  O16  1  0.375  0.869  0.842  1.0
  O  O17  1  0.131  0.625  0.658  1.0
  O  O18  1  0.974  0.789  0.165  1.0
  O  O19  1  0.026  0.211  0.835  1.0
[/CIF]
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The compound described by MgSiO3 crystallizes in the monoclinic C2/c space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted MgO6 octahedra that share corners with four equivalent Si(1)O4 tetrahedra, edges with three equivalent Mg(2)O6 octahedra, and edges with two equivalent Si(1)O4 tetrahedra. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(3) 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 three equivalent Mg(1)O6 octahedra. Si(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 27-61°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Mg(1), one Mg(2), and one Si(1) atom. In the third O site, O(3) is bonded to one Mg(1), two equivalent Mg(2), and one Si(1) atom to form a mixture of distorted edge and corner-sharing OMg3Si trigonal pyramids. is represented by the Crystallographic Information File (CIF) [CIF]
data_MgSiO3
_symmetry_space_group_name_H-M   'P 1'
_cell_length_a   6.660
_cell_length_b   6.660
_cell_length_c   5.307
_cell_angle_alpha   73.138
_cell_angle_beta   73.138
_cell_angle_gamma   81.757
_symmetry_Int_Tables_number   1
_cell_volume   215.117
_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  0.262  0.738  0.250  1.0
  Mg  Mg1  1  0.902  0.098  0.250  1.0
  Mg  Mg2  1  0.738  0.262  0.750  1.0
  Mg  Mg3  1  0.098  0.902  0.750  1.0
  Si  Si4  1  0.618  0.798  0.797  1.0
  Si  Si5  1  0.202  0.382  0.703  1.0
  Si  Si6  1  0.798  0.618  0.297  1.0
  Si  Si7  1  0.382  0.202  0.203  1.0
  O  O8  1  0.682  0.621  0.620  1.0
  O  O9  1  0.621  0.682  0.120  1.0
  O  O10  1  0.869  0.375  0.342  1.0
  O  O11  1  0.625  0.131  0.158  1.0
  O  O12  1  0.318  0.379  0.380  1.0
  O  O13  1  0.789  0.974  0.665  1.0
  O  O14  1  0.379  0.318  0.880  1.0
  O  O15  1  0.211  0.026  0.335  1.0
  O  O16  1  0.375  0.869  0.842  1.0
  O  O17  1  0.131  0.625  0.658  1.0
  O  O18  1  0.974  0.789  0.165  1.0
  O  O19  1  0.026  0.211  0.835  1.0
[/CIF]
.