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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 ...
On the other hand, the nitrobenzene resonance structures have positive charges around the ring system: The nitro group can withdraw electron density through resonance. Attack occurs at the meta position, since the (partial) formal positive charges at the ortho and para positions indicate electron deficiency at these positions.
The mesomeric effect however, deals with restructuring and occurs when the electron pair of the substituents shift around. The inductive effect only acts on alpha carbons, while the mesomeric utilizes pi bonds between atoms. [4] While these two paths often lead to the similar molecules and resonance structures, the mechanism is different.
[4] [5] An extended version of this model is used to describe the whole class of hypervalent molecules such as phosphorus pentafluoride and sulfur hexafluoride as well as multi-center π-bonding such as ozone and sulfur trioxide. There are also molecules such as diborane (B 2 H 6) and dialane (Al 2 H 6) which have three-center two-electron bond ...
today's connections game answers for wednesday, december 11, 2024: 1. utopia: paradise, seventh heaven, shangri-la, xanadu 2. things you shake: hairspray, magic 8 ...
4-Aminophenol (or para-aminophenol or p-aminophenol) is an organic compound with the formula H 2 NC 6 H 4 OH. Typically available as a white powder, [ 3 ] it is commonly used as a developer for black-and-white film , marketed under the name Rodinal .
4. Greece. I went on a long trip to Greece. Latifah Al-Hazza. I spent months island-hopping between the Cycladic Islands and Athens and loved every minute of it.