Ethylenediaminetetraacetic acid formation constants

Ethylenediaminetetraacetic acid, analogs, complexes of, 3 277 chelation by, 3 276-277 cobalt complex of, 3 281 complexes, 3 277-278 formation constant of, 3 273-274 -nickel, 3 17-18 stability of, 3 266-267 reaction with metal ions, 3 62 Ethylene dibromide, irradiation of, 5 196 4,5-Ethylenedithio-1,3-dithiole-2-thione based supramolecular complexes, 46 200-204 Ethylene glycol, 32 4... 

EDTA (ethylenediaminetetraacetic acid) (H02CCH2)2NCH2CH2N-(CH2C02H)2, the most widely used reagent for complexometric titrations. It forms 1 1 complexes with virtually all cations with a charge of 2 or more, effective formation constant Equilibrium constant for formation of a complex under a particular stated set of conditions, such as pH, ionic strength, and concentration of auxiliary complexing species. Also called conditional formation constant. 

EDTA Complexes. Ethylenediaminetetraacetic acid (EDTA) and its homologues form the most stable known complexes of plutonium. This discussion will be limited to EDTA, which is most likely to be found in the environment as a result of its use as a medium for the addition of soluble iron to soils. The equilibrium constant for formation of the 1 1 chelate of plutonium(III), as given by the expression... 

The powerful metal chelator, EDTA (ethylenediaminetetraacetic acid), is an efficient extracting agent for organically bound trace metal cations in soils at pH 6 and higher. The formation constants, for some metal-EDTA complexes in water are given below ... 

A further prerequisite for an indium complex to be useful for nuclear medicine applications is that it be resistant to exchange with the plasma protein transferrin. Indium binds to transferrin at the Fe binding site with a stability constant (/f ) of lO in the presence of bicarbonate [7]. The formation constants of indium with ethylenediaminetetraacetic acid (EDTA) (log = 25.0) and DTPA (log Ki = 29.0) are such that at infinite dilution equilibrium would favor the formation of indium transferrin [8J. The slow dissociation of indium from these complexes hinders the formation of indium transferrin. 

Figure 8 Formation constants of Ln with some aminocarboxylic acids. DCTA, 1,2-diaminocyclohexanetetraacetic acid EDTA, ethylenediaminetetraacetic acid EGTA, l,2-bis(di(carboxymethyl)aminoethoxy)ethane...

A fact that Fe(III)-EDTA(ethylenediaminetetraacetic acid) and analogous complexes form a dimer in addition to a hydroxo-complex in weak acid solution is well known [6,7], The presence of a hydroxo-complex in weak acid solution was also considered in the V(III)-picolinate system because formation of dimer was supposed. Although there are few reports on the equilibrium constant between monomer and dimer, electrode reaction at peak IIIc reveals the existence of dimer(not shown in Fig. 5, but only reduction peak appeared in the pH range above 5.0 and scan rate above 20 V/sec). 

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