Abstract Different synthesis routes have been studied for the preparation of a new oxoalkoxide, Er 2Ti 4O 2(OEt) 18(HOEt) 2(Et=C 2H 5). The compound was best prepared by reacting KOEt and Ti(OEt) 4first with water and then with ErCl 3. The structure was determined by single-crystal X-ray diffraction, showing the unit cell to have the monoclinic space group symmetry, P2 1/ n, and the lattice constants a=15.180(2) Å, b=12.693(2) Å, c=16.602(3) Å and β=98.91(1)° and to contain two formula units. The final Rvalue was 0.053 (w R=0.077). The molecule contains three of the most commonly found structure fragments of alkoxides, namely the C 2 h fragment of Ti 4(OEt) 16(Er 2Ti 2O 6), the M 4( μ 4-O) fragment (Er 2Ti 2O), and the face-sharing MO 6octahedra, with M=Ti 4+. IR studies revealed that the molecular structure of the alkoxide was retained to a large extent when the alkoxide was dissolved in 4:1 ethanol:toluene and hexane solvents.