Eleven organotin compounds (OTC) were potentiometrically titrated in methanol to determine their standard potentials, E 0 , and ionization constants, K eq . The classical method for potentiometry yielded nonreproducible results; therefore an alternate titration method was developed using the OTC as the titrant. The standard potentials, E 0 , and ionization constants, K eq , were determined by extrapolating the potentiometric titration data to 1.0 M concentration. The extrapolation yielded two E 0 values for the two different species in the solution. The titrations yielded a different end point potentials for anion ligands attached to the same OTC moiety, yet all the equilibrium ionization constants for a given organotin moiety, e.g., Bu 3 Sn or Bu 2 Sn, were approximately the same (approximately TBT ร
10 03 and DBT ร
10 04 ). This suggests a difference in the energy level of the cation species for the accepting of an electron but a dissociation constant which is independent of anion moiety. The two E 0 potentials for each of the OTC in methanol are as follows: tri-n-butyltin fluoride, 0.02 and 0.07; tri-n-butyltin chloride, 0.13 and 0.17; tri-n-butyltin bromide, 0.17 and 0.23; tri-n-butyltin iodide, 0.21 and 0.22; tri-n-butyltin laurate, /0.01 and 0.03; tri-n-butyltin naphthalate, 00.01 and 0.00; tri-n-butyltin benzoate, 0.08 and 0.10; di-nbutyltin fluoride, 0.07 and 0.10; di-n-butyltin chloride, 0.22 and 0.49; di-n-butyltin bromide, 0.24, and 0.29; and diphenyltin chloride, 0.21 and 0.33.