MgFeSiO5 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(9) atom. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(3), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Fe(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Fe(2), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Mg(2), one Fe(1), and one Fe(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one Fe(2) atom.
MgFeSiO5 crystallizes in the triclinic P1 space group. There are two inequivalent Mg sites. In the first Mg site, Mg(1) is bonded in a 7-coordinate geometry to one O(1), one O(10), one O(2), one O(3), one O(4), one O(7), and one O(8) atom. The Mg(1)-O(1) bond length is 2.30 Å. The Mg(1)-O(10) bond length is 2.05 Å. The Mg(1)-O(2) bond length is 2.32 Å. The Mg(1)-O(3) bond length is 2.46 Å. The Mg(1)-O(4) bond length is 2.57 Å. The Mg(1)-O(7) bond length is 2.25 Å. The Mg(1)-O(8) bond length is 2.20 Å. In the second Mg site, Mg(2) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), one O(6), and one O(9) atom. The Mg(2)-O(1) bond length is 2.56 Å. The Mg(2)-O(2) bond length is 2.48 Å. The Mg(2)-O(3) bond length is 2.36 Å. The Mg(2)-O(4) bond length is 2.26 Å. The Mg(2)-O(5) bond length is 2.23 Å. The Mg(2)-O(6) bond length is 2.22 Å. The Mg(2)-O(9) bond length is 2.05 Å. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to one O(10), one O(2), one O(4), one O(5), one O(7), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(2)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. The Fe(1)-O(10) bond length is 1.87 Å. The Fe(1)-O(2) bond length is 2.07 Å. The Fe(1)-O(4) bond length is 2.07 Å. The Fe(1)-O(5) bond length is 1.94 Å. The Fe(1)-O(7) bond length is 1.93 Å. The Fe(1)-O(9) bond length is 1.87 Å. In the second Fe site, Fe(2) is bonded to one O(1), one O(10), one O(3), one O(6), one O(8), and one O(9) atom to form FeO6 octahedra that share corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Si(1)O4 tetrahedra, and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. The Fe(2)-O(1) bond length is 2.07 Å. The Fe(2)-O(10) bond length is 1.87 Å. The Fe(2)-O(3) bond length is 2.07 Å. The Fe(2)-O(6) bond length is 1.94 Å. The Fe(2)-O(8) bond length is 1.94 Å. The Fe(2)-O(9) bond length is 1.88 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(1), one O(2), one O(7), and one O(8) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. The Si(1)-O(1) bond length is 1.64 Å. The Si(1)-O(2) bond length is 1.64 Å. The Si(1)-O(7) bond length is 1.65 Å. The Si(1)-O(8) bond length is 1.65 Å. In the second Si site, Si(2) is bonded to one O(3), one O(4), one O(5), and one O(6) atom to form SiO4 tetrahedra that share corners with two equivalent Fe(1)O6 octahedra and corners with two equivalent Fe(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-56°. The Si(2)-O(3) bond length is 1.64 Å. The Si(2)-O(4) bond length is 1.64 Å. The Si(2)-O(5) bond length is 1.65 Å. The Si(2)-O(6) bond length is 1.65 Å. There are ten inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(2), and one Si(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(1), and one Si(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(2), and one Si(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Mg(1), one Mg(2), one Fe(1), and one Si(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Fe(1), and one Si(2) atom. In the sixth O site, O(6) is bonded in a distorted trigonal non-coplanar geometry to one Mg(2), one Fe(2), and one Si(2) atom. In the seventh O site, O(7) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(1), and one Si(1) atom. In the eighth O site, O(8) is bonded in a distorted trigonal non-coplanar geometry to one Mg(1), one Fe(2), and one Si(1) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Mg(2), one Fe(1), and one Fe(2) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to one Mg(1), one Fe(1), and one Fe(2) atom.