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More recently, Clar's rule was further extended to diradicaloids in their singlet state. [4] Two representations of the same resonance structure of anthracene. Above, each covalent bond between carbon atoms is represented by one or two segments. Below, the aromatic π-sextet is put in evidence by means of a circle.
According to Clar's rule, [20] the resonance structure of a PAH that has the largest number of disjoint aromatic pi sextets—i.e. benzene-like moieties—is the most important for the characterization of the properties of that PAH. [21] Benzene-substructure resonance analysis for Clar's rule
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.
Triangulene (also known as Clar's hydrocarbon) is the smallest triplet-ground-state polybenzenoid. [1] It exists as a biradical with the chemical formula C 22 H 12. [2] It was first hypothesized by Czech chemist Erich Clar in 1953. [3]
Two different resonance forms of benzene (top) combine to produce an average structure (bottom). In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugation alone.
This configuration allows for the electrons in the molecule's pi system to be delocalized around the ring, increasing the molecule's stability. The molecule cannot be represented by one structure, but rather a resonance hybrid of different structures, such as with the two resonance structures of benzene.
The lawsuit came a day after 23 Republican attorneys general from states including West Virginia, North Dakota and Texas challenged a different EPA rule that limits the amount of mercury and other ...
A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). [1] Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, properties, and applications of organic heterocycles. [2]