Proposal of the partial logarithm of stability constant (PLSC) and its application to rare earth diethylenetriamine-N,N,N′,N′,N″,-pentaacetic acid (DTPA) complexes

The purpose of this article is to propose the idea of “a partial stability constant” for the complex formation of polyamine polyacetic acids with tripositive rare earth ion. Each coordinating group has its own characteristic stability constant,i.e.,“the partial stability constant” and simple numerical addition can be used among the partial logarithm of the stability constant (PLSC), for explanation of the total stability constants. The structures of the rare earth－diethylenetriamine-N,N,N′,N′,N″-pentaacetic acid (DTPA) complexes in aqueous solution has been discussed from the point of PLSC.