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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
Erich Clar (23 August 1902 – 27 March 1987) was an Austrian organic chemist, born in Hřensko, who studied polycyclic aromatic hydrocarbon chemistry. He is considered as the father of that field. [ 1 ]
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.
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]
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 .