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一、EDTA络合物的稳定常数 1.络合物的绝对稳定常数K_(MY): 金属隔子M~(+n)(n为+2～+4价)与EDTA(EDTA是乙二胺四乙酸二钠盐的简称,用Na_2H_2Y表示)形成1:1型MY络合物。 如:M~(++)+H_2Y-=MY-+2H~+ 当络合反应达平衡时:K_(MY)~稳=[MY]/[M][Y] 式中:[MY]金属离子M与EDTA络合物的浓度 [M]:未络合的金属离子浓度 [Y]:未络合的EDTA阴离子浓度 K_(MY):络合物绝对稳定常数。此值愈大,表示形成络台物愈稳定。绝对稳定常数不受浓度、酸度等外因的改变而发生变化。
First, the stability constant of EDTA complex 1. The absolute stability constant of the complex K MY: The metal compartment M ~ (+ n) (n is +2 ~ +4 valence) and EDTA (EDTA is ethylenediamine Tetraacetic acid disodium salt abbreviation, with Na_2H_2Y said) to form 1: 1 type MY complex. Such as: M ~ (++) + H_2Y- = MY- + 2H ~ + When the complexation reaction reaches equilibrium: K_ (MY) ~ stable = [MY] / [M] [Y] Where: Concentration of ion M and EDTA complex [M]: Uncomplexed metal ion concentration [Y]: Uncomplexed EDTA anion concentration K_ (MY): Complex absolute stability constant. The greater this value, said the more stable the formation of complex network station. Absolute stability constant from the concentration, acidity and other external factors change.