Abstract Diluted solid solutions of ‘3d’ (chromium) and ‘4f’ (neodymium and cerium) elements in the K 2NiF 4-type 1/1 perovskite rock salt intergrowth structure of mixed aluminates were investigated in order to get evidence of mutual influence phenomena. Crystal chemical data obtained for the solid solution Y 1 − xNd xCaCr yAl 1 − yO 4 (x ≤ 0.1; y ≤ 0.1) point to the existence of an Nd(III)OCr(III) coupling in the bridge bonds which connect the perovskite and rock salt slabs. A non-statistical distribution of Nd(III) is very likely to occur in the rock salt slabs. A magnetochemical characterization brings the proof of a partial reduction of Ce(IV) to Ce(III) in the composition Y 0.9Ce 0.1CaAlO 4, as in Y 0.8Ce 0.1Ca 1.1AlO 4 the only (IV) valence state is found. The simultaneous presence of Ce(IV) and Ce(III) is confirmed by the results of structure calculations, in terms of a splitting of the CeO distances in the rock salt slabs.