MgLaI5 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one I(1), one I(3), one I(4), and one I(5) atom to form MgI4 tetrahedra that share corners with four equivalent La(1)I6 octahedra. The corner-sharing octahedral tilt angles range from 32-59°. La(1) is bonded to one I(1), one I(3), one I(4), one I(5), and two equivalent I(2) atoms to form LaI6 octahedra that share corners with two equivalent La(1)I6 octahedra and corners with four equivalent Mg(1)I4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. There are five inequivalent I sites. In the first I site, I(1) is bonded in a bent 120 degrees geometry to one Mg(1) and one La(1) atom. In the second I site, I(2) is bonded in a bent 150 degrees geometry to two equivalent La(1) atoms. In the third I site, I(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one La(1) atom. In the fourth I site, I(4) is bonded in a bent 120 degrees geometry to one Mg(1) and one La(1) atom. In the fifth I site, I(5) is bonded in a bent 120 degrees geometry to one Mg(1) and one La(1) atom.
MgLaI5 crystallizes in the monoclinic P2_1/c space group. Mg(1) is bonded to one I(1), one I(3), one I(4), and one I(5) atom to form MgI4 tetrahedra that share corners with four equivalent La(1)I6 octahedra. The corner-sharing octahedral tilt angles range from 32-59°. The Mg(1)-I(1) bond length is 2.80 Å. The Mg(1)-I(3) bond length is 2.82 Å. The Mg(1)-I(4) bond length is 2.76 Å. The Mg(1)-I(5) bond length is 2.75 Å. La(1) is bonded to one I(1), one I(3), one I(4), one I(5), and two equivalent I(2) atoms to form LaI6 octahedra that share corners with two equivalent La(1)I6 octahedra and corners with four equivalent Mg(1)I4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. The La(1)-I(1) bond length is 3.19 Å. The La(1)-I(3) bond length is 3.19 Å. The La(1)-I(4) bond length is 3.17 Å. The La(1)-I(5) bond length is 3.22 Å. There is one shorter (3.18 Å) and one longer (3.19 Å) La(1)-I(2) bond length. There are five inequivalent I sites. In the first I site, I(1) is bonded in a bent 120 degrees geometry to one Mg(1) and one La(1) atom. In the second I site, I(2) is bonded in a bent 150 degrees geometry to two equivalent La(1) atoms. In the third I site, I(3) is bonded in a bent 150 degrees geometry to one Mg(1) and one La(1) atom. In the fourth I site, I(4) is bonded in a bent 120 degrees geometry to one Mg(1) and one La(1) atom. In the fifth I site, I(5) is bonded in a bent 120 degrees geometry to one Mg(1) and one La(1) atom.