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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.
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 ...
[8] [9] The ionic structures of tropylium perchlorate (C 7 H + 7 ClO − 4) and tropylium iodide (C 7 H + 7 I −) have been confirmed by X-ray crystallography. [10] The bond length of the carbon-carbon bonds is longer (147 pm) than those of benzene (140 pm) but still shorter than those of a typical single-bonded species like ethane (154 pm).
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]
The selectivity for alpha over beta substitution can be rationalized in terms of the resonance structures of the intermediate: for the alpha substitution intermediate, seven resonance structures can be drawn, of which four preserve an aromatic ring.
10H 8. It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odour that is detectable at concentrations as low as 0.08 ppm by mass. As an aromatic hydrocarbon, naphthalene's structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs.
[10] [11] If so, then the canonical form H−N + ≡C−O − is the major resonance structure. However, classic vibrational analysis would indicate that the 2268.8 cm −1 is the asymmetric N=C=O stretch, as per Colthup et al., [ 12 ] as well as the NIST Chemistry WebBook, [ 13 ] which also reports the corresponding symmetric N=C=O stretch ...
A one-dimensional finite square potential is given by = {, < <,,,The sign of determines whether the square potential is a well or a barrier.To study the phenomena of resonance, the time-independent Schrödinger equation for a stationary state of a massive particle with energy > is solved: