Charge delocalization in phenoxide ions increases their stability. In phenoxide ions, the negative charge is delocalized over the aromatic ring through resonance, creating a more stable structure. The negative charge is spread across multiple atoms, reducing the energy of the ion and making it less reactive. In contrast, the phenol molecule is less stable than the phenoxide ion because it lacks this charge delocalization. The lone pair on the oxygen is localized, making the oxygen more nucleophilic and the molecule more reactive. Phenol readily donates a proton, forming the more stable phenoxide ion.