K2La6OsI12 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 6-coordinate geometry to one I(1), one I(4), two equivalent I(3), and two equivalent I(6) atoms. There are three inequivalent La sites. In the first La site, La(1) is bonded to one Os(1), one I(1), one I(2), one I(4), and two equivalent I(5) atoms to form a mixture of distorted corner and edge-sharing LaOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-48°. In the second La site, La(2) is bonded to one Os(1), one I(3), one I(5), one I(6), and two equivalent I(2) atoms to form a mixture of corner and edge-sharing LaOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-48°. In the third La site, La(3) is bonded to one Os(1), one I(1), one I(3), one I(6), and two equivalent I(4) atoms to form a mixture of corner and edge-sharing LaOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. Os(1) is bonded to two equivalent La(1), two equivalent La(2), and two equivalent La(3) atoms to form OsLa6 octahedra that share edges with two equivalent I(6)K2La2 trigonal pyramids. There are six inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to one K(1), one La(1), and one La(3) atom. In the second I site, I(2) is bonded in a 3-coordinate geometry to one La(1) and two equivalent La(2) atoms. In the third I site, I(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(1), one La(2), and one La(3) atom. In the fourth I site, I(4) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one La(1), and two equivalent La(3) atoms. In the fifth I site, I(5) is bonded in a distorted T-shaped geometry to one La(2) and two equivalent La(1) atoms. In the sixth I site, I(6) is bonded to two equivalent K(1), one La(2), and one La(3) atom to form distorted IK2La2 trigonal pyramids that share corners with two equivalent I(6)K2La2 trigonal pyramids and  an edgeedge with one Os(1)La6 octahedra.
K2La6OsI12 crystallizes in the monoclinic P2_1/c space group. K(1) is bonded in a 6-coordinate geometry to one I(1), one I(4), two equivalent I(3), and two equivalent I(6) atoms. The K(1)-I(1) bond length is 3.53 Å. The K(1)-I(4) bond length is 4.03 Å. There is one shorter (4.02 Å) and one longer (4.08 Å) K(1)-I(3) bond length. There is one shorter (3.60 Å) and one longer (3.68 Å) K(1)-I(6) bond length. There are three inequivalent La sites. In the first La site, La(1) is bonded to one Os(1), one I(1), one I(2), one I(4), and two equivalent I(5) atoms to form a mixture of distorted corner and edge-sharing LaOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-48°. The La(1)-Os(1) bond length is 2.81 Å. The La(1)-I(1) bond length is 3.22 Å. The La(1)-I(2) bond length is 3.29 Å. The La(1)-I(4) bond length is 3.30 Å. There is one shorter (3.25 Å) and one longer (3.49 Å) La(1)-I(5) bond length. In the second La site, La(2) is bonded to one Os(1), one I(3), one I(5), one I(6), and two equivalent I(2) atoms to form a mixture of corner and edge-sharing LaOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-48°. The La(2)-Os(1) bond length is 2.99 Å. The La(2)-I(3) bond length is 3.24 Å. The La(2)-I(5) bond length is 3.30 Å. The La(2)-I(6) bond length is 3.27 Å. There is one shorter (3.32 Å) and one longer (3.59 Å) La(2)-I(2) bond length. In the third La site, La(3) is bonded to one Os(1), one I(1), one I(3), one I(6), and two equivalent I(4) atoms to form a mixture of corner and edge-sharing LaOsI5 octahedra. The corner-sharing octahedral tilt angles range from 0-7°. The La(3)-Os(1) bond length is 2.82 Å. The La(3)-I(1) bond length is 3.23 Å. The La(3)-I(3) bond length is 3.33 Å. The La(3)-I(6) bond length is 3.35 Å. There is one shorter (3.29 Å) and one longer (3.47 Å) La(3)-I(4) bond length. Os(1) is bonded to two equivalent La(1), two equivalent La(2), and two equivalent La(3) atoms to form OsLa6 octahedra that share edges with two equivalent I(6)K2La2 trigonal pyramids. There are six inequivalent I sites. In the first I site, I(1) is bonded in a distorted T-shaped geometry to one K(1), one La(1), and one La(3) atom. In the second I site, I(2) is bonded in a 3-coordinate geometry to one La(1) and two equivalent La(2) atoms. In the third I site, I(3) is bonded in a distorted rectangular see-saw-like geometry to two equivalent K(1), one La(2), and one La(3) atom. In the fourth I site, I(4) is bonded in a distorted rectangular see-saw-like geometry to one K(1), one La(1), and two equivalent La(3) atoms. In the fifth I site, I(5) is bonded in a distorted T-shaped geometry to one La(2) and two equivalent La(1) atoms. In the sixth I site, I(6) is bonded to two equivalent K(1), one La(2), and one La(3) atom to form distorted IK2La2 trigonal pyramids that share corners with two equivalent I(6)K2La2 trigonal pyramids and  an edgeedge with one Os(1)La6 octahedra.