LaY3Ti4O14 crystallizes in the trigonal R-3m space group. La(1) is bonded to two equivalent O(3) and six equivalent O(1) atoms to form LaO8 hexagonal bipyramids that share edges with six equivalent Y(1)O8 hexagonal bipyramids and edges with six equivalent Ti(2)O6 octahedra. Y(1) is bonded to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms to form distorted YO8 hexagonal bipyramids that share edges with two equivalent La(1)O8 hexagonal bipyramids, edges with four equivalent Y(1)O8 hexagonal bipyramids, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Ti(2)O6 octahedra. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to six equivalent O(2) atoms to form TiO6 octahedra that share corners with six equivalent Ti(2)O6 octahedra and edges with six equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 48°. In the second Ti site, Ti(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Ti(2)O6 octahedra, edges with two equivalent La(1)O8 hexagonal bipyramids, and edges with four equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-48°. There are three inequivalent O sites. In the first O site, O(3) is bonded to one La(1) and three equivalent Y(1) atoms to form OLaY3 tetrahedra that share corners with four equivalent O(3)LaY3 tetrahedra, corners with six equivalent O(1)LaYTi2 tetrahedra, corners with six equivalent O(2)Y2Ti2 tetrahedra, edges with three equivalent O(1)LaYTi2 tetrahedra, and edges with three equivalent O(2)Y2Ti2 tetrahedra. In the second O site, O(1) is bonded to one La(1), one Y(1), and two equivalent Ti(2) atoms to form distorted OLaYTi2 tetrahedra that share corners with two equivalent O(3)LaY3 tetrahedra, corners with four equivalent O(2)Y2Ti2 tetrahedra, corners with eight equivalent O(1)LaYTi2 tetrahedra,  an edgeedge with one O(3)LaY3 tetrahedra, edges with two equivalent O(1)LaYTi2 tetrahedra, and edges with two equivalent O(2)Y2Ti2 tetrahedra. In the third O site, O(2) is bonded to two equivalent Y(1), one Ti(1), and one Ti(2) atom to form distorted OY2Ti2 tetrahedra that share corners with two equivalent O(3)LaY3 tetrahedra, corners with four equivalent O(1)LaYTi2 tetrahedra, corners with eight equivalent O(2)Y2Ti2 tetrahedra,  an edgeedge with one O(3)LaY3 tetrahedra, edges with two equivalent O(1)LaYTi2 tetrahedra, and edges with two equivalent O(2)Y2Ti2 tetrahedra.
LaY3Ti4O14 crystallizes in the trigonal R-3m space group. La(1) is bonded to two equivalent O(3) and six equivalent O(1) atoms to form LaO8 hexagonal bipyramids that share edges with six equivalent Y(1)O8 hexagonal bipyramids and edges with six equivalent Ti(2)O6 octahedra. Both La(1)-O(3) bond lengths are 2.32 Å. All La(1)-O(1) bond lengths are 2.56 Å. Y(1) is bonded to two equivalent O(1), two equivalent O(3), and four equivalent O(2) atoms to form distorted YO8 hexagonal bipyramids that share edges with two equivalent La(1)O8 hexagonal bipyramids, edges with four equivalent Y(1)O8 hexagonal bipyramids, edges with two equivalent Ti(1)O6 octahedra, and edges with four equivalent Ti(2)O6 octahedra. Both Y(1)-O(1) bond lengths are 2.51 Å. Both Y(1)-O(3) bond lengths are 2.19 Å. All Y(1)-O(2) bond lengths are 2.53 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to six equivalent O(2) atoms to form TiO6 octahedra that share corners with six equivalent Ti(2)O6 octahedra and edges with six equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 48°. All Ti(1)-O(2) bond lengths are 1.98 Å. In the second Ti site, Ti(2) is bonded to two equivalent O(2) and four equivalent O(1) atoms to form TiO6 octahedra that share corners with two equivalent Ti(1)O6 octahedra, corners with four equivalent Ti(2)O6 octahedra, edges with two equivalent La(1)O8 hexagonal bipyramids, and edges with four equivalent Y(1)O8 hexagonal bipyramids. The corner-sharing octahedral tilt angles range from 47-48°. Both Ti(2)-O(2) bond lengths are 1.99 Å. All Ti(2)-O(1) bond lengths are 1.98 Å. There are three inequivalent O sites. In the first O site, O(3) is bonded to one La(1) and three equivalent Y(1) atoms to form OLaY3 tetrahedra that share corners with four equivalent O(3)LaY3 tetrahedra, corners with six equivalent O(1)LaYTi2 tetrahedra, corners with six equivalent O(2)Y2Ti2 tetrahedra, edges with three equivalent O(1)LaYTi2 tetrahedra, and edges with three equivalent O(2)Y2Ti2 tetrahedra. In the second O site, O(1) is bonded to one La(1), one Y(1), and two equivalent Ti(2) atoms to form distorted OLaYTi2 tetrahedra that share corners with two equivalent O(3)LaY3 tetrahedra, corners with four equivalent O(2)Y2Ti2 tetrahedra, corners with eight equivalent O(1)LaYTi2 tetrahedra,  an edgeedge with one O(3)LaY3 tetrahedra, edges with two equivalent O(1)LaYTi2 tetrahedra, and edges with two equivalent O(2)Y2Ti2 tetrahedra. In the third O site, O(2) is bonded to two equivalent Y(1), one Ti(1), and one Ti(2) atom to form distorted OY2Ti2 tetrahedra that share corners with two equivalent O(3)LaY3 tetrahedra, corners with four equivalent O(1)LaYTi2 tetrahedra, corners with eight equivalent O(2)Y2Ti2 tetrahedra,  an edgeedge with one O(3)LaY3 tetrahedra, edges with two equivalent O(1)LaYTi2 tetrahedra, and edges with two equivalent O(2)Y2Ti2 tetrahedra.