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详细地研究了铈与钛铁试剂的配位反应及怖(Ⅲ)与铈(Ⅳ)配合物的相互转化。无色的铈(Ⅲ)配合物在pH>4.5时生成,吸收光谱中于256nm与311nm处有两个吸收峰。当pH>6时铈(Ⅲ)配合物能自发氧化成紫红色的铈(Ⅳ)配合物。后者在510nm处有一宽吸收峰。氧化程度与氧化速度随pH增大而增加;pH>9时氧化完全。加入醇或酮等与水互溶的有机溶剂能促进铈(Ⅳ)配合物的生成并使之稳定。测定了铈(Ⅲ)与铈(Ⅳ)配合物的组成及其稳定常数。这些常数多数未见文献报道。
The coordination reaction of cerium with ilmenite and the interconversion of Ce (Ⅳ) with cerium (Ⅳ) have been studied in detail. The colorless cerium (III) complex is formed at pH> 4.5 and has two absorption peaks at 256 nm and 311 nm in the absorption spectrum. When pH> 6, the cerium (III) complex spontaneously oxidized into the purple cerium (Ⅳ) complex. The latter has a broad absorption peak at 510 nm. The degree of oxidation and the rate of oxidation increased with increasing pH; the oxidation was complete at pH> 9. Addition of a water-miscible organic solvent such as alcohol or ketone promotes the formation and stabilization of the cerium (IV) complex. The composition and stability constants of cerium (Ⅲ) and cerium (Ⅳ) complexes were determined. Most of these constants have not been reported in the literature.