AH+
, the carbinol B, and the quinonoidal base A. Equilibrium between the two neutral
forms occurs exclusively by way of the flavylium cation. Hydration of the flavylium cation
involves the formation of a C-O bond and a proton transfer. The existence of very small
amounts of a third neutral form, the chalcone C, a prototropic tautomer of the carbinol B, has
also been reported (Brouillard, et al, 1977)