LaCaAl3O7 crystallizes in the orthorhombic Cmm2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(5), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. La(1) is bonded in a 8-coordinate geometry to one O(2), one O(6), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form corner-sharing AlO4 tetrahedra. In the second Al site, Al(2) is bonded to one O(2), one O(5), and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. In the third Al site, Al(3) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. There are six inequivalent O sites. In the first O site, O(5) is bonded to two equivalent Ca(1) and two equivalent Al(2) atoms to form distorted OCa2Al2 tetrahedra that share corners with two equivalent O(2)Ca2LaAl tetrahedra, corners with two equivalent O(1)CaLa2Al tetrahedra, and edges with two equivalent O(2)Ca2LaAl tetrahedra. In the second O site, O(6) is bonded to two equivalent La(1) and two equivalent Al(1) atoms to form distorted OLa2Al2 tetrahedra that share corners with two equivalent O(2)Ca2LaAl tetrahedra, corners with two equivalent O(1)CaLa2Al tetrahedra, and edges with two equivalent O(1)CaLa2Al tetrahedra. In the third O site, O(1) is bonded to one Ca(1), two equivalent La(1), and one Al(1) atom to form distorted OCaLa2Al tetrahedra that share  a cornercorner with one O(5)Ca2Al2 tetrahedra,  a cornercorner with one O(6)La2Al2 tetrahedra, corners with four equivalent O(2)Ca2LaAl tetrahedra,  an edgeedge with one O(1)CaLa2Al tetrahedra, and  an edgeedge with one O(6)La2Al2 tetrahedra. In the fourth O site, O(2) is bonded to two equivalent Ca(1), one La(1), and one Al(2) atom to form distorted OCa2LaAl tetrahedra that share  a cornercorner with one O(5)Ca2Al2 tetrahedra,  a cornercorner with one O(6)La2Al2 tetrahedra, corners with four equivalent O(1)CaLa2Al tetrahedra,  an edgeedge with one O(5)Ca2Al2 tetrahedra, and  an edgeedge with one O(2)Ca2LaAl tetrahedra. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one La(1), one Al(1), and one Al(3) atom. In the sixth O site, O(4) is bonded in a 2-coordinate geometry to one Ca(1), one La(1), one Al(2), and one Al(3) atom.
LaCaAl3O7 crystallizes in the orthorhombic Cmm2 space group. Ca(1) is bonded in a 8-coordinate geometry to one O(1), one O(5), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms. The Ca(1)-O(1) bond length is 2.49 Å. The Ca(1)-O(5) bond length is 2.43 Å. Both Ca(1)-O(2) bond lengths are 2.58 Å. Both Ca(1)-O(3) bond lengths are 2.49 Å. Both Ca(1)-O(4) bond lengths are 2.95 Å. La(1) is bonded in a 8-coordinate geometry to one O(2), one O(6), two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms. The La(1)-O(2) bond length is 2.43 Å. The La(1)-O(6) bond length is 2.51 Å. Both La(1)-O(1) bond lengths are 2.61 Å. Both La(1)-O(3) bond lengths are 2.87 Å. Both La(1)-O(4) bond lengths are 2.47 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded to one O(1), one O(6), and two equivalent O(3) atoms to form corner-sharing AlO4 tetrahedra. The Al(1)-O(1) bond length is 1.75 Å. The Al(1)-O(6) bond length is 1.77 Å. Both Al(1)-O(3) bond lengths are 1.78 Å. In the second Al site, Al(2) is bonded to one O(2), one O(5), and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. The Al(2)-O(2) bond length is 1.74 Å. The Al(2)-O(5) bond length is 1.75 Å. Both Al(2)-O(4) bond lengths are 1.78 Å. In the third Al site, Al(3) is bonded to two equivalent O(3) and two equivalent O(4) atoms to form corner-sharing AlO4 tetrahedra. Both Al(3)-O(3) bond lengths are 1.77 Å. Both Al(3)-O(4) bond lengths are 1.77 Å. There are six inequivalent O sites. In the first O site, O(5) is bonded to two equivalent Ca(1) and two equivalent Al(2) atoms to form distorted OCa2Al2 tetrahedra that share corners with two equivalent O(2)Ca2LaAl tetrahedra, corners with two equivalent O(1)CaLa2Al tetrahedra, and edges with two equivalent O(2)Ca2LaAl tetrahedra. In the second O site, O(6) is bonded to two equivalent La(1) and two equivalent Al(1) atoms to form distorted OLa2Al2 tetrahedra that share corners with two equivalent O(2)Ca2LaAl tetrahedra, corners with two equivalent O(1)CaLa2Al tetrahedra, and edges with two equivalent O(1)CaLa2Al tetrahedra. In the third O site, O(1) is bonded to one Ca(1), two equivalent La(1), and one Al(1) atom to form distorted OCaLa2Al tetrahedra that share  a cornercorner with one O(5)Ca2Al2 tetrahedra,  a cornercorner with one O(6)La2Al2 tetrahedra, corners with four equivalent O(2)Ca2LaAl tetrahedra,  an edgeedge with one O(1)CaLa2Al tetrahedra, and  an edgeedge with one O(6)La2Al2 tetrahedra. In the fourth O site, O(2) is bonded to two equivalent Ca(1), one La(1), and one Al(2) atom to form distorted OCa2LaAl tetrahedra that share  a cornercorner with one O(5)Ca2Al2 tetrahedra,  a cornercorner with one O(6)La2Al2 tetrahedra, corners with four equivalent O(1)CaLa2Al tetrahedra,  an edgeedge with one O(5)Ca2Al2 tetrahedra, and  an edgeedge with one O(2)Ca2LaAl tetrahedra. In the fifth O site, O(3) is bonded in a 4-coordinate geometry to one Ca(1), one La(1), one Al(1), and one Al(3) atom. In the sixth O site, O(4) is bonded in a 2-coordinate geometry to one Ca(1), one La(1), one Al(2), and one Al(3) atom.