Valence (chemistry)

About: Valence (chemistry) is a research topic. Over the lifetime, 24937 publications have been published within this topic receiving 645252 citations. The topic is also known as: valency.

Valence tautomeric transitions with thermal hysteresis around room temperature and photoinduced effects observed in a cobalt-tetraoxolene complex.

Abstract: A dinuclear complex, [(CoTPA)2(DHBQ)](PF6)3, has been successfully synthesized that exhibits a valence tautomeric transition with a distinct hysteresis effect (13 K) around room temperature and photoinduced valence tautomerism under low temperature.

Photoemission Measurements of the Valence Levels of Amorphous Si O 2

Abstract: The complete valence band in amorphous Si${\mathrm{O}}_{2}$ has been examined by photoelectron spectroscopy at photon energies of 21.2, 26.9, 40.8, and 1486.6 eV. The spectra show emission from an 11.2-eV-wide $p$-derived valence band and from the oxygen $2s$ level at 20.2 eV below the valence-band edge. Four pieces of structure in the $p$ bands are related to the single bonding and the two nonbonding orbitals of the ${\mathrm{O}}^{\ensuremath{-}\ensuremath{-}}$ ion. A narrow, nonbonding level found at the valence-band edge may cause lattice trapping of valence-band holes.

High Pressure Electrides: A Predictive Chemical and Physical Theory

Abstract: ConspectusElectrides, in which electrons occupy interstitial regions in the crystal and behave as anions, appear as new phases for many elements (and compounds) under high pressure. We propose a unified theory of high pressure electrides (HPEs) by treating electrons in the interstitial sites as filling the quantized orbitals of the interstitial space enclosed by the surrounding atom cores, generating what we call an interstitial quasi-atom, ISQ.With increasing pressure, the energies of the valence orbitals of atoms increase more significantly than the ISQ levels, due to repulsion, exclusion by the atom cores, effectively giving the valence electrons less room in which to move. At a high enough pressure, which depends on the element and its orbitals, the frontier atomic electron may become higher in energy than the ISQ, resulting in electron transfer to the interstitial space and the formation of an HPE.By using a He lattice model to compress (with minimal orbital interaction at moderate pressures between ...