Er2TiO5 crystallizes in the monoclinic C2/c space group. Er(1) is bonded in a 6-coordinate geometry to one O(3), two equivalent O(1), and three equivalent O(2) atoms. Ti(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Er(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to three equivalent Er(1) and one Ti(1) atom. In the third O site, O(3) is bonded to two equivalent Er(1) and two equivalent Ti(1) atoms to form distorted corner-sharing OEr2Ti2 trigonal pyramids.
Er2TiO5 crystallizes in the monoclinic C2/c space group. Er(1) is bonded in a 6-coordinate geometry to one O(3), two equivalent O(1), and three equivalent O(2) atoms. The Er(1)-O(3) bond length is 2.33 Å. There is one shorter (2.16 Å) and one longer (2.18 Å) Er(1)-O(1) bond length. There are a spread of Er(1)-O(2) bond distances ranging from 2.22-2.51 Å. Ti(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms to form corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 51°. Both Ti(1)-O(1) bond lengths are 1.97 Å. Both Ti(1)-O(2) bond lengths are 1.96 Å. Both Ti(1)-O(3) bond lengths are 2.08 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to two equivalent Er(1) and one Ti(1) atom. In the second O site, O(2) is bonded in a 4-coordinate geometry to three equivalent Er(1) and one Ti(1) atom. In the third O site, O(3) is bonded to two equivalent Er(1) and two equivalent Ti(1) atoms to form distorted corner-sharing OEr2Ti2 trigonal pyramids.