MgSiO3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. In the second Mg site, Mg(2) is bonded to one O(3), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and edges with two equivalent Mg(2)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(2)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-60°. In the second Si site, Si(2) is bonded to one O(4), one O(6), and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(2)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-62°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Si(2) atoms. In the second O site, O(6) is bonded in a distorted T-shaped geometry to one Mg(1), one Mg(2), and one Si(2) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Mg(2), and one Si(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Mg(1) and two equivalent Si(1) atoms. In the fifth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Mg(2), and one Si(1) atom. In the sixth O site, O(4) is bonded to one Mg(1), two equivalent Mg(2), and one Si(2) atom to form distorted corner-sharing OMg3Si trigonal pyramids.
MgSiO3 crystallizes in the orthorhombic Pna2_1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and one O(6) atom. The Mg(1)-O(1) bond length is 2.06 Å. The Mg(1)-O(2) bond length is 2.54 Å. The Mg(1)-O(3) bond length is 2.05 Å. The Mg(1)-O(4) bond length is 2.07 Å. The Mg(1)-O(5) bond length is 2.32 Å. The Mg(1)-O(6) bond length is 2.06 Å. In the second Mg site, Mg(2) is bonded to one O(3), one O(6), two equivalent O(1), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, and edges with two equivalent Mg(2)O6 octahedra. The Mg(2)-O(3) bond length is 2.04 Å. The Mg(2)-O(6) bond length is 2.04 Å. There is one shorter (2.07 Å) and one longer (2.26 Å) Mg(2)-O(1) bond length. There is one shorter (2.09 Å) and one longer (2.22 Å) Mg(2)-O(4) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(2)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-60°. The Si(1)-O(1) bond length is 1.63 Å. The Si(1)-O(3) bond length is 1.61 Å. There is one shorter (1.66 Å) and one longer (1.67 Å) Si(1)-O(2) bond length. In the second Si site, Si(2) is bonded to one O(4), one O(6), and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(2)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 27-62°. The Si(2)-O(4) bond length is 1.63 Å. The Si(2)-O(6) bond length is 1.61 Å. There is one shorter (1.67 Å) and one longer (1.69 Å) Si(2)-O(5) bond length. There are six inequivalent O sites. In the first O site, O(5) is bonded in a 3-coordinate geometry to one Mg(1) and two equivalent Si(2) atoms. In the second O site, O(6) is bonded in a distorted T-shaped geometry to one Mg(1), one Mg(2), and one Si(2) atom. In the third O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), two equivalent Mg(2), and one Si(1) atom. In the fourth O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Mg(1) and two equivalent Si(1) atoms. In the fifth O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Mg(2), and one Si(1) atom. In the sixth O site, O(4) is bonded to one Mg(1), two equivalent Mg(2), and one Si(2) atom to form distorted corner-sharing OMg3Si trigonal pyramids.