稀土元素与变色酸双偶氮型试剂常可形成β型络合物。尽管试剂的结构不同时,轻、重稀土与它形成β型络合物能力的差别也较大,但大都存在共显色效应。华东师大有机合成研究室的实验表明,偶氮氯膦-pN(CPA-pN)与重稀土元素可形成β型络合物。我们在实验中发现,在pH1左右时钇易与CPA-pN形成β型络合物,而镧、铈、镱、 Rare earth elements and chromotropic acid disazo-type reagents often form β-type complexes. Despite the different structures of the reagents, the light and heavy rare earths have a greater difference in their ability to form β-type complexes, but most of them have the effect of co-coloring. Experiments conducted by the East China Normal University Organic Synthesis Laboratory show that CPA-pN (CPA-pN) and heavy rare earth elements can form β-type complexes. We found in the experiment that yttrium readily forms a beta-type complex with CPA-pN at about pH 1 whereas lanthanum, cerium, ytterbium,