calculation from literature values with standard SSA and SSD at ionic strength of 1M, log K for pHzpc 8.4-8.6 in brackets for pHzpc 9-9.5 »Fe-O<1-> + Ag<1+> = »Fe-O-Ag logK = 7.4 (7.0) »Fe-OH = »Fe-O<1-> + H<1+> pK2 = -logK = 12.3 sum »Fe-OH + Ag<1+> = »Fe-O-Ag + H<1+> logK=7.4(7.0)-12.3 = -4.9(-5.3)