reference electrode

Journal of The Electrochemical Society

Linear correlations are analyzed between the empirical electronegativities χa of metals and non-metals and their standard potentials Eo. The correlation intersection corresponds to the transfer from metals to non-metals, characterized by the intermediate electronegativity χa,interm and the standard potential Eo ~+ 0.5 V SHE which is close to Billiter potential +0.475 V SHE. It is concluded that χa,interm and Eo ~ +0.5 V SHE would define some hypothetical substance (neither metal nor non-metal) without its own chemical activity. This would be due to the intermediate non-specific (definite coulomb) bond of its outer electrons being insufficiently unstable (as metallic bonds) for breaking and insufficiently stable (as non-metallic bonds) for accepting electrons in half-reactions. Spontaneous half-reactions are analyzed as interactions of Red - and Ox - forms with water molecules on electrodes due to break Red + H2O → Ox + neinterm and formation Ox + neinterm + H2O → Red of specific (chemical) electron bonds, where neinterm are electrons in the absence of a specific bond with Ox-forms but at the definite coulomb bond with them. The instant division of electrons, ions, polarization water molecules of formed intermediate complexes leads to the appearance of double-electric layers on electrodes.

The Correlation Between the Electronegativities and the Standard Potentials