Ilościowe kryteria aromatyczności [Cz.2 art.: Aromatyczność : podstawowe pojęcia współczesnej chemii organicznej (Wiad.Chem. 2000, Nr 5-6)]

Aromataic character is manifested in p-electron systems by particular physicochemical properties: an increase of stability, averaging of bond lengths, particular magnetic properties and chemical reactivity preffering retention of the p-electron structure. These properties are used for definitions of quantative measures of aromaticity (indices of aromaticity). In principle they do not always predict the aromatic character in a uniform way. Additionally each of the used criteria is biased by some inadequacies or lack of generality. The energetic criterion defined as resonance energy or aromatic stabilisation energy measures the total aromaticity and strongly depends on the choice of reference states and/or reactions,). The same is true for the magnetic criterion - exaltation of the diamagnetic susceptibility. Geometric parameters seem to be the most general and may be used for estimation of both local and global aromatic character. Each of the criteria may be used providing a proper reference state can be defined. Application of variously defined indices of aromaticity is critcally discussed.