Relationship between the Atomic Structure and Electrochemistry. 1. Electric Force, Standard Reduction Potential E°,...

The relationship among the standard reaction Gibbs free energy ΔG°, the standard reduction potential E°, and the atomic structure parameters of radius, nuclear charge, and isoelectronic orbitals nl is accomplished through the attraction electric force F _elec. In relationship with E°, it was necessary to define two new reference scales: E ₀ ^° with a final state of E° in the element, which allowed to have a parabolic trend of ΔG° versus F _elec, and E ^°,0 whose final state is the ion with a more negative charge (e.g., -1, -2, -3). The relationship with ΔG° is related to the concept of chemical stability, and the relationship with E ^°,0 is more related to the concept of electronegativity. In relationship with ΔG°, it was necessary to predict the values of possible new cations and noncommon cations in order to find a better trend of ΔG° versus F _elec, whose stability is analyzed by Frost diagrams of the isoelectronic series. This dependence of ΔG° on F _elec is split into two terms. The first term indicates the behavior of the minimum of ΔG° for each isoelectronic orbital nl, while the second term deals with the parabolic trend of this orbital. For the minima of the configuration np⁶, a hysteresis behavior of the minima of ΔG° is found: an exponential behavior from periods 1 and 2 and a sigmoidal behavior from periods 5 and 4 to interpolate period 3. It is also found that the proximity of unfilled np or (n + 1)s orbitals induces instability of the ion in configurations ns²/nd²/4f² and nd¹⁰/nd⁸(n + 1)s², respectively. On the contrary, the stability of the orbitals np⁶ does not depend on the neighboring empty (n + 1)s⁰ orbitals. Both phenomena can be explained by the stability of the configuration of noble gas np⁶ and the nd¹⁰(n + 1)s² configuration. We have also found that it is possible to increase the reduction potential E ^°,0 (macroscopic electronegativity), although the electric force F _elec decreases because the orbital overlap influences the electronegativity.