La9Ni5O19 crystallizes in the orthorhombic Fmm2 space group. There are five inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(5), and four equivalent O(2) atoms. In the second La site, La(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. In the third La site, La(3) is bonded in a 9-coordinate geometry to one O(4), one O(8), two equivalent O(3), two equivalent O(6), and three equivalent O(7) atoms. In the fourth La site, La(4) is bonded in a 8-coordinate geometry to one O(5), one O(7), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. In the fifth La site, La(5) is bonded in a 8-coordinate geometry to one O(7), two equivalent O(3), two equivalent O(6), and three equivalent O(8) atoms. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(4), one O(5), two equivalent O(2), and two equivalent O(3) atoms to form distorted NiO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra and corners with two equivalent Ni(2)O5 square pyramids. The corner-sharing octahedral tilt angles are 15°. In the second Ni site, Ni(2) is bonded to one O(1) and four equivalent O(2) atoms to form corner-sharing NiO5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the third Ni site, Ni(3) is bonded to one O(7), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 6-coordinate geometry to one La(4), one La(5), three equivalent La(3), and one Ni(3) atom. In the second O site, O(8) is bonded in a 5-coordinate geometry to one La(3), three equivalent La(5), and one Ni(3) atom. In the third O site, O(1) is bonded in a 5-coordinate geometry to two equivalent La(1), two equivalent La(2), and one Ni(2) atom. In the fourth O site, O(2) is bonded to one La(1), one La(2), one La(4), one Ni(1), and one Ni(2) atom to form distorted OLa3Ni2 square pyramids that share corners with two equivalent O(2)La3Ni2 square pyramids, corners with two equivalent O(4)La4Ni square pyramids,  an edgeedge with one O(4)La4Ni square pyramid, edges with two equivalent O(2)La3Ni2 square pyramids, and  a faceface with one O(2)La3Ni2 square pyramid. In the fifth O site, O(3) is bonded in a 6-coordinate geometry to one La(2), one La(3), one La(4), one La(5), one Ni(1), and one Ni(3) atom. In the sixth O site, O(4) is bonded to one La(2), one La(3), two equivalent La(4), and one Ni(1) atom to form distorted OLa4Ni square pyramids that share corners with two equivalent O(6)La4Ni2 octahedra, corners with two equivalent O(4)La4Ni square pyramids, corners with four equivalent O(2)La3Ni2 square pyramids, and edges with two equivalent O(2)La3Ni2 square pyramids. The corner-sharing octahedral tilt angles are 48°. In the seventh O site, O(5) is bonded in a 5-coordinate geometry to one La(1), one La(4), two equivalent La(2), and one Ni(1) atom. In the eighth O site, O(6) is bonded to two equivalent La(3), two equivalent La(5), and two equivalent Ni(3) atoms to form distorted OLa4Ni2 octahedra that share corners with two equivalent O(4)La4Ni square pyramids and faces with two equivalent O(6)La4Ni2 octahedra.
La9Ni5O19 crystallizes in the orthorhombic Fmm2 space group. There are five inequivalent La sites. In the first La site, La(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(5), and four equivalent O(2) atoms. Both La(1)-O(1) bond lengths are 2.82 Å. Both La(1)-O(5) bond lengths are 2.59 Å. All La(1)-O(2) bond lengths are 2.47 Å. In the second La site, La(2) is bonded in a 8-coordinate geometry to one O(1), one O(4), two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms. The La(2)-O(1) bond length is 2.50 Å. The La(2)-O(4) bond length is 2.36 Å. Both La(2)-O(2) bond lengths are 2.56 Å. Both La(2)-O(3) bond lengths are 2.68 Å. Both La(2)-O(5) bond lengths are 2.78 Å. In the third La site, La(3) is bonded in a 9-coordinate geometry to one O(4), one O(8), two equivalent O(3), two equivalent O(6), and three equivalent O(7) atoms. The La(3)-O(4) bond length is 2.37 Å. The La(3)-O(8) bond length is 2.30 Å. Both La(3)-O(3) bond lengths are 2.78 Å. Both La(3)-O(6) bond lengths are 2.55 Å. There are two shorter (2.77 Å) and one longer (3.04 Å) La(3)-O(7) bond length. In the fourth La site, La(4) is bonded in a 8-coordinate geometry to one O(5), one O(7), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The La(4)-O(5) bond length is 2.32 Å. The La(4)-O(7) bond length is 2.53 Å. Both La(4)-O(2) bond lengths are 2.46 Å. Both La(4)-O(3) bond lengths are 2.67 Å. Both La(4)-O(4) bond lengths are 2.80 Å. In the fifth La site, La(5) is bonded in a 8-coordinate geometry to one O(7), two equivalent O(3), two equivalent O(6), and three equivalent O(8) atoms. The La(5)-O(7) bond length is 2.34 Å. Both La(5)-O(3) bond lengths are 2.50 Å. Both La(5)-O(6) bond lengths are 2.66 Å. There is one shorter (2.46 Å) and two longer (2.78 Å) La(5)-O(8) bond lengths. There are three inequivalent Ni sites. In the first Ni site, Ni(1) is bonded to one O(4), one O(5), two equivalent O(2), and two equivalent O(3) atoms to form distorted NiO6 octahedra that share corners with two equivalent Ni(3)O6 octahedra and corners with two equivalent Ni(2)O5 square pyramids. The corner-sharing octahedral tilt angles are 15°. The Ni(1)-O(4) bond length is 2.14 Å. The Ni(1)-O(5) bond length is 2.49 Å. Both Ni(1)-O(2) bond lengths are 1.95 Å. Both Ni(1)-O(3) bond lengths are 1.98 Å. In the second Ni site, Ni(2) is bonded to one O(1) and four equivalent O(2) atoms to form corner-sharing NiO5 square pyramids. The corner-sharing octahedral tilt angles are 7°. The Ni(2)-O(1) bond length is 2.03 Å. All Ni(2)-O(2) bond lengths are 1.98 Å. In the third Ni site, Ni(3) is bonded to one O(7), one O(8), two equivalent O(3), and two equivalent O(6) atoms to form corner-sharing NiO6 octahedra. The corner-sharing octahedral tilt angles range from 11-15°. The Ni(3)-O(7) bond length is 2.27 Å. The Ni(3)-O(8) bond length is 2.17 Å. Both Ni(3)-O(3) bond lengths are 1.96 Å. Both Ni(3)-O(6) bond lengths are 1.97 Å. There are eight inequivalent O sites. In the first O site, O(7) is bonded in a 6-coordinate geometry to one La(4), one La(5), three equivalent La(3), and one Ni(3) atom. In the second O site, O(8) is bonded in a 5-coordinate geometry to one La(3), three equivalent La(5), and one Ni(3) atom. In the third O site, O(1) is bonded in a 5-coordinate geometry to two equivalent La(1), two equivalent La(2), and one Ni(2) atom. In the fourth O site, O(2) is bonded to one La(1), one La(2), one La(4), one Ni(1), and one Ni(2) atom to form distorted OLa3Ni2 square pyramids that share corners with two equivalent O(2)La3Ni2 square pyramids, corners with two equivalent O(4)La4Ni square pyramids,  an edgeedge with one O(4)La4Ni square pyramid, edges with two equivalent O(2)La3Ni2 square pyramids, and  a faceface with one O(2)La3Ni2 square pyramid. In the fifth O site, O(3) is bonded in a 6-coordinate geometry to one La(2), one La(3), one La(4), one La(5), one Ni(1), and one Ni(3) atom. In the sixth O site, O(4) is bonded to one La(2), one La(3), two equivalent La(4), and one Ni(1) atom to form distorted OLa4Ni square pyramids that share corners with two equivalent O(6)La4Ni2 octahedra, corners with two equivalent O(4)La4Ni square pyramids, corners with four equivalent O(2)La3Ni2 square pyramids, and edges with two equivalent O(2)La3Ni2 square pyramids. The corner-sharing octahedral tilt angles are 48°. In the seventh O site, O(5) is bonded in a 5-coordinate geometry to one La(1), one La(4), two equivalent La(2), and one Ni(1) atom. In the eighth O site, O(6) is bonded to two equivalent La(3), two equivalent La(5), and two equivalent Ni(3) atoms to form distorted OLa4Ni2 octahedra that share corners with two equivalent O(4)La4Ni square pyramids and faces with two equivalent O(6)La4Ni2 octahedra.