La3OsO7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. In the second La site, La(2) is bonded to one O(3), two equivalent O(1), and four equivalent O(2) atoms to form distorted LaO7 pentagonal bipyramids that share corners with two equivalent Os(1)O6 octahedra, corners with three equivalent La(2)O7 pentagonal bipyramids, edges with two equivalent Os(1)O6 octahedra, and edges with two equivalent La(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. Os(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form OsO6 octahedra that share corners with two equivalent Os(1)O6 octahedra, corners with four equivalent La(2)O7 pentagonal bipyramids, and edges with four equivalent La(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent La(1) and two equivalent La(2) atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one La(1), two equivalent La(2), and one Os(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent La(2) and two equivalent Os(1) atoms.
La3OsO7 crystallizes in the orthorhombic Cmcm space group. There are two inequivalent La sites. In the first La site, La(1) is bonded in a body-centered cubic geometry to four equivalent O(1) and four equivalent O(2) atoms. All La(1)-O(1) bond lengths are 2.42 Å. All La(1)-O(2) bond lengths are 2.77 Å. In the second La site, La(2) is bonded to one O(3), two equivalent O(1), and four equivalent O(2) atoms to form distorted LaO7 pentagonal bipyramids that share corners with two equivalent Os(1)O6 octahedra, corners with three equivalent La(2)O7 pentagonal bipyramids, edges with two equivalent Os(1)O6 octahedra, and edges with two equivalent La(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 33°. The La(2)-O(3) bond length is 2.62 Å. There is one shorter (2.33 Å) and one longer (2.34 Å) La(2)-O(1) bond length. There are two shorter (2.48 Å) and two longer (2.53 Å) La(2)-O(2) bond lengths. Os(1) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form OsO6 octahedra that share corners with two equivalent Os(1)O6 octahedra, corners with four equivalent La(2)O7 pentagonal bipyramids, and edges with four equivalent La(2)O7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. Both Os(1)-O(3) bond lengths are 2.01 Å. All Os(1)-O(2) bond lengths are 1.98 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded to two equivalent La(1) and two equivalent La(2) atoms to form a mixture of edge and corner-sharing OLa4 tetrahedra. In the second O site, O(2) is bonded in a 4-coordinate geometry to one La(1), two equivalent La(2), and one Os(1) atom. In the third O site, O(3) is bonded in a 4-coordinate geometry to two equivalent La(2) and two equivalent Os(1) atoms.