The F(0)tot point estimates reveal a statistically significantly larger difference among the alkali earth chlorides we surveyed (bottom halves of Fig. ). These differences do not follow the ionic radius of each cation species, which matches findings from previous work, including from calorimetric measurements. Ca 2+ appears to have the largest field screening effect in the cation series, with F(0)tot reaching close to 0 V at 100 mM ionic strength. The larger ions, strontium and barium, come next, while the smallest (and hardest) ion, magnesium, lowers F(0)tot the least relative to NaCl.