<p>Resultant concepts in information theory (IT) combine probability and current contributions, due to the modulus and phase of molecular state, respectively. Classical (probability) and resultant (wavefunction) descriptors are summarized and relations between entropy and information densities are investigated. The connection between the Shannon and Fisher measures is commented upon and <i>quantum</i>-generalized. The gradient of <i>entropy</i>-density determines the amplitude of the local <i>information</i>-content, the squared gradient of the <i>wavefunction</i>-logarithm. The discrete and continuous probability and improbability descriptors are compared and their normalizations explored. The symmetric binary channel of communication theory, the IT model of an elementary chemical bond, is reexamined and its complementary probability (<i>signal</i>-switching) and improbability (<i>signal</i>-conservation) entropies are interpreted as the <i>orbital</i>-uncertainty (“noise”, covalency) and <i>orbital</i>-certainty (“determinicity”, iconicity) descriptors. Localization/delocalization terms in the binary entropy function are identified and additive and nonadditive bond components are extracted.</p> Graphical abstract <p>Classical and nonclassical entropy and information measures, probability andimprobability descriptors, and components of chemical bonds, along with thesymmetric binary channel of communication theory.</p> <p></p>