Pr0.7Sr0.3Fe1-xNxO3-δ (PSFN; x=0.2-0.5) compounds were synthesized and characterized by powder X-ray diffraction (XRD), thermal expansion coefficient (TEC) measurements, electrical conductivity and electrochemical impedance spectroscopy on cone-shaped electrodes on a Ce0.9Gd0.1O1.95 (CGO10) electrolyte. T he main phase of the powders belongs to the orthorhombic crystal system. The conductivities are fairly high, e.g., around 450 scm(-1) at 600 &DEG; C for the x=0.3 compound. The TEC of the compounds is close to the values of ceria-based electrolytes PSEN showed hysteresis in the temperature dependence of the conductivity, TEC and area-specific polarization resistance R-pol. It is considered that the hysteresis was caused by relatively slow adjustment of the oxygen stoichiometry. The electrochemical La0.6Sr0.4Fe0.8Co0.2O3-δ. © 2004 Elsevier B.V. All rights reserved.