pH=8 used during the preparation of Sr-Ba-Nb precursor gels was determined by calculation of the conditional formation constant Kcf of Sr-EDTA and Ba-EDTA complexes.

• 通过计算Sr-EDTA和Ba-EDTA配合物的条件形成常数Kcf及实验确定获得稳定Sr-Ba-Nb前驱体凝胶的最佳pH=8.