It is shown that the ion La~(+3)is conn? eted with an oxygen atom in sulfadiazine group in a form of coordinate bond while a covalence bond is formed between the ion La~(+3) and a nitrogen atom located on pyrinidine cycle.

• 分析表明；稀土离子La~(3+)与磺酰胺基中氧原子形成了配位键；同时又与嘧啶环上的氮原子形成了共价键.