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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.
The lone electron in NO 2 also means that this compound is a free radical, so the formula for nitrogen dioxide is often written as • NO 2. The reddish-brown color is a consequence of preferential absorption of light in the blue region of the spectrum (400–500 nm), although the absorption extends throughout the visible (at shorter ...
The nitrate ion (NO − 3), for instance, must form a double bond between nitrogen and one of the oxygens to satisfy the octet rule for nitrogen. However, because the molecule is symmetrical, it does not matter which of the oxygens forms the double bond. In this case, there are three possible resonance structures.
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 structure of an organic nitro compound. In organic chemistry, nitro compounds are organic compounds that contain one or more nitro functional groups (−NO 2).The nitro group is one of the most common explosophores (functional group that makes a compound explosive) used globally.
One classic reaction is the Chichibabin reaction (Aleksei Chichibabin, 1914) in which pyridine is reacted with an alkali-metal amide such as sodium amide to form 2-aminopyridine. [ 6 ] In the compound methyl 3-nitropyridine-4-carboxylate, the meta nitro group is actually displaced by fluorine with cesium fluoride in DMSO at 120 °C.
The nitronium ion, [N O 2] +, is a cation.It is an onium ion because its nitrogen atom has +1 charge, similar to ammonium ion [NH 4] +.It is created by the removal of an electron from the paramagnetic nitrogen dioxide molecule NO 2, or the protonation of nitric acid HNO 3 (with removal of H 2 O).
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 ...