MgTiAs2O7 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one O(1), one O(5), one O(6), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share corners with two equivalent Ti(1)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. Ti(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form TiO4 tetrahedra that share  a cornercorner with one As(1)O4 tetrahedra and corners with two equivalent Mg(1)O5 trigonal bipyramids. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one Ti(1)O4 tetrahedra and corners with three equivalent Mg(1)O5 trigonal bipyramids. In the second As site, As(2) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a trigonal planar geometry to one Mg(1), one Ti(1), and one As(2) atom. In the second O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one As(1) atom. In the third O site, O(7) is bonded in a bent 120 degrees geometry to one Ti(1) and one As(2) atom. In the fourth O site, O(1) is bonded in a bent 120 degrees geometry to one Mg(1) and one Ti(1) atom. In the fifth O site, O(2) is bonded in a linear geometry to one Ti(1) and one As(1) atom. In the sixth O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one As(1) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one As(1) and one As(2) atom.
MgTiAs2O7 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one O(1), one O(5), one O(6), and two equivalent O(3) atoms to form MgO5 trigonal bipyramids that share corners with two equivalent Ti(1)O4 tetrahedra, corners with three equivalent As(1)O4 tetrahedra, and  an edgeedge with one Mg(1)O5 trigonal bipyramid. The Mg(1)-O(1) bond length is 2.01 Å. The Mg(1)-O(5) bond length is 2.16 Å. The Mg(1)-O(6) bond length is 2.03 Å. There is one shorter (2.08 Å) and one longer (2.09 Å) Mg(1)-O(3) bond length. Ti(1) is bonded to one O(1), one O(2), one O(5), and one O(7) atom to form TiO4 tetrahedra that share  a cornercorner with one As(1)O4 tetrahedra and corners with two equivalent Mg(1)O5 trigonal bipyramids. The Ti(1)-O(1) bond length is 1.71 Å. The Ti(1)-O(2) bond length is 1.92 Å. The Ti(1)-O(5) bond length is 1.93 Å. The Ti(1)-O(7) bond length is 1.85 Å. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(2), one O(3), one O(4), and one O(6) atom to form AsO4 tetrahedra that share  a cornercorner with one Ti(1)O4 tetrahedra and corners with three equivalent Mg(1)O5 trigonal bipyramids. The As(1)-O(2) bond length is 1.72 Å. The As(1)-O(3) bond length is 1.72 Å. The As(1)-O(4) bond length is 1.76 Å. The As(1)-O(6) bond length is 1.69 Å. In the second As site, As(2) is bonded in a 3-coordinate geometry to one O(4), one O(5), and one O(7) atom. The As(2)-O(4) bond length is 1.90 Å. The As(2)-O(5) bond length is 1.84 Å. The As(2)-O(7) bond length is 1.80 Å. There are seven inequivalent O sites. In the first O site, O(5) is bonded in a trigonal planar geometry to one Mg(1), one Ti(1), and one As(2) atom. In the second O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Mg(1) and one As(1) atom. In the third O site, O(7) is bonded in a bent 120 degrees geometry to one Ti(1) and one As(2) atom. In the fourth O site, O(1) is bonded in a bent 120 degrees geometry to one Mg(1) and one Ti(1) atom. In the fifth O site, O(2) is bonded in a linear geometry to one Ti(1) and one As(1) atom. In the sixth O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Mg(1) and one As(1) atom. In the seventh O site, O(4) is bonded in a bent 120 degrees geometry to one As(1) and one As(2) atom.