Mg2SiO4 crystallizes in the orthorhombic Imma space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) 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 four equivalent Mg(3)O6 octahedra. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with three equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-61°. There are four inequivalent O sites. In the first O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(3), and one Si(1) atom. In the second O site, O(3) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form edge-sharing OMg5 square pyramids. In the third O site, O(4) is bonded in a trigonal planar geometry to one Mg(2) and two equivalent Si(1) atoms. In the fourth O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(3), and one Si(1) atom.
Mg2SiO4 crystallizes in the orthorhombic Imma space group. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(2) and four equivalent O(1) 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 four equivalent Mg(3)O6 octahedra. Both Mg(1)-O(2) bond lengths are 2.14 Å. All Mg(1)-O(1) bond lengths are 2.07 Å. In the second Mg site, Mg(2) is bonded to one O(3), one O(4), and four equivalent O(1) atoms to form MgO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The Mg(2)-O(3) bond length is 2.06 Å. The Mg(2)-O(4) bond length is 2.12 Å. All Mg(2)-O(1) bond lengths are 2.11 Å. In the third Mg site, Mg(3) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(3)O6 octahedra, corners with four equivalent Si(1)O4 tetrahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with three equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles are 16°. Both Mg(3)-O(1) bond lengths are 2.15 Å. Both Mg(3)-O(2) bond lengths are 2.15 Å. Both Mg(3)-O(3) bond lengths are 2.04 Å. Si(1) is bonded to one O(2), one O(4), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with three equivalent Mg(1)O6 octahedra, corners with three equivalent Mg(2)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 47-61°. The Si(1)-O(2) bond length is 1.66 Å. The Si(1)-O(4) bond length is 1.72 Å. Both Si(1)-O(1) bond lengths are 1.65 Å. There are four inequivalent O sites. In the first O site, O(2) is bonded in a rectangular see-saw-like geometry to one Mg(1), two equivalent Mg(3), and one Si(1) atom. In the second O site, O(3) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form edge-sharing OMg5 square pyramids. In the third O site, O(4) is bonded in a trigonal planar geometry to one Mg(2) and two equivalent Si(1) atoms. In the fourth O site, O(1) is bonded in a rectangular see-saw-like geometry to one Mg(1), one Mg(2), one Mg(3), and one Si(1) atom.