Likewise, we expect that the estimates of the F(0)tot drop across the oxide:water interface we report here for the various salts we surveyed provides an experimental benchmark for mean field and/or atomistic models that include dipolar and multipolar contributions to the popular Gouy-Chapman-Stern theory, the "standard model". Ionizing surface potential measurements published in 2021 by Allen and coworkers show that the surface potential ("c potential", no relation to c reported here) of the (nominally uncharged) pure air:water interface is as low as ~ -500 mV, and that it is slightly less negative (~ -400 mV) at the air:electrolyte (1 M NaCl and 1M Na2SO4) interface.