Search results
Results from the WOW.Com Content Network
Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.
Expressing resonance when drawing Lewis structures may be done either by drawing each of the possible resonance forms and placing double-headed arrows between them or by using dashed lines to represent the partial bonds (although the latter is a good representation of the resonance hybrid which is not, formally speaking, a Lewis structure).
In chemistry, the mesomeric effect (or resonance effect) is a property of substituents or functional groups in a chemical compound. It is defined as the polarity produced in the molecule by the interaction of two pi bonds or between a pi bond and lone pair of electrons present on an adjacent atom. [ 1 ]
Formaldehyde (/ f ɔːr ˈ m æ l d ɪ h aɪ d / ⓘ for-MAL-di-hide, US also / f ə r-/ ⓘ fər-) (systematic name methanal) is an organic compound with the chemical formula CH 2 O and structure H−CHO, more precisely H 2 C=O.
The field of resonance ionization spectroscopy (RIS) has largely been shaped by the formal and informal communications heralding its discovery. [13] Research papers on RIS have heavily relied on self-citation from inception, a trend which climaxed three years later with the founding of a company to commercialize the technique. [14]
In molecules which have resonance or nonclassical bonding, bond order may not be an integer.In benzene, the delocalized molecular orbitals contain 6 pi electrons over six carbons, essentially yielding half a pi bond together with the sigma bond for each pair of carbon atoms, giving a calculated bond order of 1.5 (one and a half bond).
This does not mean that a vibrational mode which is not Raman active must be IR active: in fact, it is still possible that a mode of a particular symmetry is neither Raman nor IR active. Such spectroscopically "silent" or "inactive" modes exist in molecules such as ethylene (C 2 H 4 ), benzene (C 6 H 6 ) and the tetrachloroplatinate ion (PtCl 4 ...
Clar's rule states that for a benzenoid polycyclic aromatic hydrocarbon (i.e. one with only hexagonal rings), the resonance structure with the largest number of disjoint aromatic π-sextets is the most important to characterize its chemical and physical properties. Such a resonance structure is called a Clar structure. In other words, a ...