One motivation for EQC is to facilitate for the interchangeable use of theoretically and experimentally derived data when analyzing electronic structure. Several terms in our partitioning of the chemical potential, eq. ( ), can, in principle, be estimated experimentally. Valence and core levels can be probed by photoemission spectroscopies, and so should their sensitivity to electronic perturbations. For atomic quantities, a strict connection between theory and experiment becomes harder. Core energies can be probed selectively by X-ray spectroscopy in many instances. However, attributing experimental estimates of average binding energies of valence electrons to atoms inside molecules is challenging. Developments of the resonant inelastic X-ray scattering (RIXS) technique are encouraging, as it may allow for the probing of valence levels with atomic selectivity. We intend for the outlined theory to stimulate constructive discussion on the driving forces responsible for chemistry, and the limits of chemical rationales in chemistry at large.