Mg2SiO4 crystallizes in the orthorhombic Pbam space group. Mg(1) is bonded in a 7-coordinate geometry to three equivalent O(2) and four equivalent O(1) atoms. Si(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form edge-sharing SiO6 octahedra. There are two inequivalent O sites. In the first O site, O(2) is bonded to three equivalent Mg(1) and two equivalent Si(1) atoms to form distorted OMg3Si2 trigonal bipyramids that share corners with four equivalent O(1)Mg4Si trigonal bipyramids, corners with eight equivalent O(2)Mg3Si2 trigonal bipyramids, edges with two equivalent O(2)Mg3Si2 trigonal bipyramids, and edges with six equivalent O(1)Mg4Si trigonal bipyramids. In the second O site, O(1) is bonded to four equivalent Mg(1) and one Si(1) atom to form distorted OMg4Si trigonal bipyramids that share corners with four equivalent O(2)Mg3Si2 trigonal bipyramids, corners with five equivalent O(1)Mg4Si trigonal bipyramids, edges with four equivalent O(1)Mg4Si trigonal bipyramids, and edges with six equivalent O(2)Mg3Si2 trigonal bipyramids.
Mg2SiO4 crystallizes in the orthorhombic Pbam space group. Mg(1) is bonded in a 7-coordinate geometry to three equivalent O(2) and four equivalent O(1) atoms. There are a spread of Mg(1)-O(2) bond distances ranging from 2.08-2.50 Å. There are two shorter (2.07 Å) and two longer (2.11 Å) Mg(1)-O(1) bond lengths. Si(1) is bonded to two equivalent O(1) and four equivalent O(2) atoms to form edge-sharing SiO6 octahedra. Both Si(1)-O(1) bond lengths are 1.77 Å. All Si(1)-O(2) bond lengths are 1.87 Å. There are two inequivalent O sites. In the first O site, O(2) is bonded to three equivalent Mg(1) and two equivalent Si(1) atoms to form distorted OMg3Si2 trigonal bipyramids that share corners with four equivalent O(1)Mg4Si trigonal bipyramids, corners with eight equivalent O(2)Mg3Si2 trigonal bipyramids, edges with two equivalent O(2)Mg3Si2 trigonal bipyramids, and edges with six equivalent O(1)Mg4Si trigonal bipyramids. In the second O site, O(1) is bonded to four equivalent Mg(1) and one Si(1) atom to form distorted OMg4Si trigonal bipyramids that share corners with four equivalent O(2)Mg3Si2 trigonal bipyramids, corners with five equivalent O(1)Mg4Si trigonal bipyramids, edges with four equivalent O(1)Mg4Si trigonal bipyramids, and edges with six equivalent O(2)Mg3Si2 trigonal bipyramids.