Here, < 0O > 3 and < 4O > 3 are the mean values of the interatomic A-O and B-O distances, respectively. The observed tolerance factor for a cubic perovskite is equal to 1.00. For the synthesized materials, the values of ! "#$ are in the range [0.978, 0.993] (Table ). For a fixed B element, the ! "#$ values decrease according to the A element following the trend La > Pr > Nd > Sm. This shows that the octahedral tilting and crystallographic strain increases (and ! "#$ decreases) as the size of the A species decreases. Additional parameters were obtained using the Rietveld refinement analysis. These parameters were defined so that materials presenting different crystal symmetry (orthorhombic and rhombohedral) could be compared in a consistent manner.