MgZrSi2O7 crystallizes in the orthorhombic Imma space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms to form distorted MgO8 hexagonal bipyramids that share edges with two equivalent Mg(1)O8 hexagonal bipyramids, edges with four equivalent Zr(1)O8 hexagonal bipyramids, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Si(2)O6 octahedra. Zr(1) is bonded to two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted ZrO8 hexagonal bipyramids that share edges with two equivalent Zr(1)O8 hexagonal bipyramids, edges with four equivalent Mg(1)O8 hexagonal bipyramids, edges with two equivalent Si(2)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra, corners with four equivalent Si(2)O6 octahedra, edges with two equivalent Mg(1)O8 hexagonal bipyramids, and edges with four equivalent Zr(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-46°. In the second Si site, Si(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form SiO6 octahedra that share corners with two equivalent Si(2)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Zr(1)O8 hexagonal bipyramids, and edges with four equivalent Mg(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Zr(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Si(2) atoms to form distorted OMg2Si2 tetrahedra that share corners with two equivalent O(4)Mg2Zr2 tetrahedra, corners with four equivalent O(2)Mg2Si2 tetrahedra, and  an edgeedge with one O(4)Mg2Zr2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one Zr(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded to two equivalent Mg(1) and two equivalent Zr(1) atoms to form OMg2Zr2 tetrahedra that share corners with two equivalent O(2)Mg2Si2 tetrahedra, corners with four equivalent O(4)Mg2Zr2 tetrahedra, and  an edgeedge with one O(2)Mg2Si2 tetrahedra.
MgZrSi2O7 crystallizes in the orthorhombic Imma space group. Mg(1) is bonded to two equivalent O(2), two equivalent O(4), and four equivalent O(3) atoms to form distorted MgO8 hexagonal bipyramids that share edges with two equivalent Mg(1)O8 hexagonal bipyramids, edges with four equivalent Zr(1)O8 hexagonal bipyramids, edges with two equivalent Si(1)O6 octahedra, and edges with four equivalent Si(2)O6 octahedra. Both Mg(1)-O(2) bond lengths are 2.31 Å. Both Mg(1)-O(4) bond lengths are 2.00 Å. All Mg(1)-O(3) bond lengths are 2.41 Å. Zr(1) is bonded to two equivalent O(1), two equivalent O(4), and four equivalent O(3) atoms to form distorted ZrO8 hexagonal bipyramids that share edges with two equivalent Zr(1)O8 hexagonal bipyramids, edges with four equivalent Mg(1)O8 hexagonal bipyramids, edges with two equivalent Si(2)O6 octahedra, and edges with four equivalent Si(1)O6 octahedra. Both Zr(1)-O(1) bond lengths are 2.35 Å. Both Zr(1)-O(4) bond lengths are 2.06 Å. All Zr(1)-O(3) bond lengths are 2.28 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra, corners with four equivalent Si(2)O6 octahedra, edges with two equivalent Mg(1)O8 hexagonal bipyramids, and edges with four equivalent Zr(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 45-46°. Both Si(1)-O(1) bond lengths are 1.78 Å. All Si(1)-O(3) bond lengths are 1.79 Å. In the second Si site, Si(2) is bonded to two equivalent O(2) and four equivalent O(3) atoms to form SiO6 octahedra that share corners with two equivalent Si(2)O6 octahedra, corners with four equivalent Si(1)O6 octahedra, edges with two equivalent Zr(1)O8 hexagonal bipyramids, and edges with four equivalent Mg(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 45°. Both Si(2)-O(2) bond lengths are 1.83 Å. All Si(2)-O(3) bond lengths are 1.80 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Zr(1) and two equivalent Si(1) atoms. In the second O site, O(2) is bonded to two equivalent Mg(1) and two equivalent Si(2) atoms to form distorted OMg2Si2 tetrahedra that share corners with two equivalent O(4)Mg2Zr2 tetrahedra, corners with four equivalent O(2)Mg2Si2 tetrahedra, and  an edgeedge with one O(4)Mg2Zr2 tetrahedra. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Mg(1), one Zr(1), one Si(1), and one Si(2) atom. In the fourth O site, O(4) is bonded to two equivalent Mg(1) and two equivalent Zr(1) atoms to form OMg2Zr2 tetrahedra that share corners with two equivalent O(2)Mg2Si2 tetrahedra, corners with four equivalent O(4)Mg2Zr2 tetrahedra, and  an edgeedge with one O(2)Mg2Si2 tetrahedra.