NdBaCo2-x FexO5+delta (0.0 <= x <= 2.0) series were prepared by a solid state reaction. Singe phase solid solutions were obtained within the range 0.0 <= x <= 1.4. The crystal structure of iron substituted solid solutions NdBaCo2-xFexO5+delta was described within the tetragonal unit cell a(p)xa(p)x2a(p) (S.G. P4/mmm). The substitution of cobalt for iron leads to the monotonous increase of the unit cell parameters and the unit cell volume. The values of the oxygen content in NdBaCo2-xFexO5+delta (x=0; 0.2) as a function of temperature were determined by TGA. The thermal expansion measurements of NdBaCo2-xFexO5+delta (X = 0; 0.2; 0.4; 0.6 and 0.8) were performed. Chemical expansion constituent was separated. (C) 2010 Elsevier B.V. All rights reserved.