Abstract: Interactions between neodymium, europium and acid dyes, eatiortic dyes, active dyes, and directive dyes have been studied by means of UV, NMR and IR spectrum measurements. The results show that the interaction pattern between rare-earth ions and dyes depends on the molecular structure of dyes. For most of dyes, such as cationic dyes, active dyes, directive dyes and some of acid dyes, coordination does not occur. It is possible to form complex between rare-earth ions and dyes like methyl red under certain conditions, but whether the azo group of the dye participates in the coordination stiU needs further studies. Mordant dyes, like Chrome Black AC, possessing strong coordination ability, can form complex with rare-earth ions as the mordant dyes do with Cr(Ⅲ).

Key words: dye, neodymium, europium, interaction