The manganese doped rare earth oxides Er2-xMnx O-3 (0.0 <= x <= 0.20) were synthesized by a sol-gel process and analyzed by X-ray diffraction using Rietveld refinement methods. A single phase solid solution is formed up to x = 0.15 while for x >= 0.2 a manganese oxide phase appears in the diffraction pattern. Preferential cationic distribution between the non-equivalent sites 8b and 24d of space group Ia (3) over bar is found for all samples but to a different extent. The octahedral volume and average bond length of Er-1-O for 8b site decrease while both octahedral volume and bond length of Er-2-O for 24d site increase. Magnetization measurements were done in the temperature range 5-300K. The effective magnetic moment mu(eff) is found to decrease with composition parameter x, except for sample x = 0.05 where the magnetization is enhanced. The Curie-Weiss paramagnetic temperatures indicate antiferromagnetic interaction. (C) 2012 Elsevier Ltd. All rights reserved.