Ba2YTi3O8 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with eight equivalent Ba(1)O12 cuboctahedra, faces with five equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ti(2)O6 octahedra, and faces with four equivalent Ti(1)O5 square pyramids. Y(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(3) and four equivalent O(1) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(2)O6 octahedra, corners with four equivalent Ti(1)O5 square pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. In the second Ti site, Ti(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with four equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(1)O5 square pyramids, and faces with eight equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Ti(2) atoms to form a mixture of distorted face, corner, and edge-sharing OBa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Ti(1), and one Ti(2) atom to form a mixture of distorted face, corner, and edge-sharing OBa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°.
Ba2YTi3O8 crystallizes in the tetragonal P4/mmm space group. Ba(1) is bonded to four equivalent O(1), four equivalent O(2), and four equivalent O(3) atoms to form BaO12 cuboctahedra that share corners with eight equivalent Ba(1)O12 cuboctahedra, faces with five equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ti(2)O6 octahedra, and faces with four equivalent Ti(1)O5 square pyramids. All Ba(1)-O(1) bond lengths are 3.08 Å. All Ba(1)-O(2) bond lengths are 2.80 Å. All Ba(1)-O(3) bond lengths are 2.83 Å. Y(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Y(1)-O(1) bond lengths are 2.49 Å. There are two inequivalent Ti sites. In the first Ti site, Ti(1) is bonded to one O(3) and four equivalent O(1) atoms to form TiO5 square pyramids that share  a cornercorner with one Ti(2)O6 octahedra, corners with four equivalent Ti(1)O5 square pyramids, and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. The Ti(1)-O(3) bond length is 1.95 Å. All Ti(1)-O(1) bond lengths are 2.01 Å. In the second Ti site, Ti(2) is bonded to two equivalent O(3) and four equivalent O(2) atoms to form TiO6 octahedra that share corners with four equivalent Ti(2)O6 octahedra, corners with two equivalent Ti(1)O5 square pyramids, and faces with eight equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedra are not tilted. Both Ti(2)-O(3) bond lengths are 2.13 Å. All Ti(2)-O(2) bond lengths are 2.00 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 4-coordinate geometry to two equivalent Ba(1), two equivalent Y(1), and two equivalent Ti(1) atoms. In the second O site, O(2) is bonded to four equivalent Ba(1) and two equivalent Ti(2) atoms to form a mixture of distorted face, corner, and edge-sharing OBa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°. In the third O site, O(3) is bonded to four equivalent Ba(1), one Ti(1), and one Ti(2) atom to form a mixture of distorted face, corner, and edge-sharing OBa4Ti2 octahedra. The corner-sharing octahedral tilt angles range from 0-57°.