LiNi1 - yFeyO2 samples were prepared either by nitrate or oxide methods. Using X-ray diffraction and Rietveld refinements, we show that single-phase products, iso-structural to LiNiO2 (R -3m space group) can be obtained in the 0 less than or equal to y less than or equal to 0.3 range. From AC magnetic susceptibility and magnetisation measurements, we have determined the role of the extra 3d cations in the lithium site. The relative distribution of the Ni and Fe ions in the layers has been also derived, in good agreement with Mossbauer data. (C) 2003 Published by Elsevier Science B.V.