Structural investigations of (Ca,Sr)ZrO3 and Ca(Sn,Zr)O3 perovskite compounds

(Ca (x) ,Sr1-x )ZrO3 and Ca(Sn (y) ,Zr1-y )O-3 solid solutions were synthesized by solid-state reaction at high temperature before to be studied by powder X-ray diffraction and Raman Spectroscopy. Diffraction data allow the distortion of the ABO(3) perovskite structure to be investigated according to cations substitution on A and B-sites. It is shown that distortion, characterized by I broken vertical bar, the tilt angle of BO6 octahedra, slightly increases with decreasing y content in Ca(Sn (y) ,Zr1-y )O-3 compounds and strongly decreases with decreasing x content in (Ca (x) ,Sr1-x )ZrO3 compounds. Such results are discussed in view of the relative A and B cation sizes. Raman data show that vibrational spectra are strongly affected by the cation substitution on A-site; the frequencies of most vibrational modes increase with increasing x content in (Ca (x) ,Sr1-x )ZrO3 compounds, i.e. with the decreasing mean size of the A-cation; the upper shift is observed for the 358 cm(-1) mode (a,nu/a,r = -60.1 cm(-1)/). On the other hand, the cation substitution on B-sites, slightly affect the spectra; it is shown that in most cases, the frequency of vibrational modes increases with increasing y content in Ca(Sn (y) ,Zr1-y )O-3 compounds, i.e. with the decreasing mean size of the B-cation, but that two modes (287 and 358 cm(-1)) behave differently: their frequencies decrease with the decreasing mean size of the B-cation, with a shift respectively equal to +314 and +162 cm(-1)/. Such results could be used to predict the location of different elements such as trivalent cations or radwaste elements on A- or B-site, in the perovskite structure.