Na3MgVO4 crystallizes in the orthorhombic I222 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. In the second Na site, Na(2) is bonded to four equivalent O(1) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Mg(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with four equivalent V(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. Mg(1) is bonded to four equivalent O(1) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Na(2)O4 tetrahedra, edges with two equivalent Na(2)O4 tetrahedra, and edges with two equivalent V(1)O4 tetrahedra. V(1) is bonded to four equivalent O(1) atoms to form distorted VO4 tetrahedra that share corners with eight equivalent Na(2)O4 tetrahedra and edges with two equivalent Mg(1)O4 tetrahedra. O(1) is bonded to one Na(1), two equivalent Na(2), one Mg(1), and one V(1) atom to form a mixture of distorted corner and edge-sharing ONa3MgV trigonal bipyramids.
Na3MgVO4 crystallizes in the orthorhombic I222 space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 4-coordinate geometry to four equivalent O(1) atoms. All Na(1)-O(1) bond lengths are 2.37 Å. In the second Na site, Na(2) is bonded to four equivalent O(1) atoms to form distorted NaO4 tetrahedra that share corners with two equivalent Mg(1)O4 tetrahedra, corners with four equivalent Na(2)O4 tetrahedra, corners with four equivalent V(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O4 tetrahedra. There are two shorter (2.38 Å) and two longer (2.57 Å) Na(2)-O(1) bond lengths. Mg(1) is bonded to four equivalent O(1) atoms to form distorted MgO4 tetrahedra that share corners with four equivalent Na(2)O4 tetrahedra, edges with two equivalent Na(2)O4 tetrahedra, and edges with two equivalent V(1)O4 tetrahedra. All Mg(1)-O(1) bond lengths are 1.97 Å. V(1) is bonded to four equivalent O(1) atoms to form distorted VO4 tetrahedra that share corners with eight equivalent Na(2)O4 tetrahedra and edges with two equivalent Mg(1)O4 tetrahedra. All V(1)-O(1) bond lengths are 1.96 Å. O(1) is bonded to one Na(1), two equivalent Na(2), one Mg(1), and one V(1) atom to form a mixture of distorted corner and edge-sharing ONa3MgV trigonal bipyramids.