Iii

formation of a particular framework is subject to the chemical nature (neutral or anionic) and steric profile of the ligands. Some examples of alkoxide clusters based on different Ba:Zr(Ti) ratios are shown in Figure 6. As a consequence of this combinatorial effect, the synthesis of BaZrO3 from a mixture of Ba and Zr precursors was associated with traces of Ba and Zr phases or their products in the final ceramic material, whereas BaZrO3 could be selectively synthesized from the single-source Ba-Zr precursor [BaZr(OH)(OPr')5(Pr'OH)3]2 (Eqs. (7) and (8)) [332].

[Ba(OBu) ]„ + Zr(OBu) —> BaO + ZrO2 + Ba2ZrO4 + BaZrO3 (7)

Minor products

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