What is a phenoxide ion?

Question

Brooklyn Barber · Accepted Answer

A phenoxide ion is the conjugate base of phenol. It looks like:

According to the Bronsted-Lowry theory of acids and bases, an acid is a molecule that donates #H^+# ions, and a base is a molecule that takes them up again. Using the instance of #NH_3 + H_2O -> NH_4^+ + HO^-# then #NH_3# acts like a base and #H_2O# acts like an acid, based on the Bronsted-Lowry definitions above. This makes #NH_4^+# into a conjugate acid (because it would, given the chance, give up hydrogen ions) and #HO^-# the conjugate base (since it would now accept hydrogen). Phenoxide is a conjugate base, which means it is formed from an acid that has given up its hydrogen. This acid is a phenol molecule, which is a benzene ring with a hydroxyl group. The hydrogen of the hydroxyl leaves, and an #O^-# remains, forming the 'oxide ion' part of the phenoxide ion. 'Phenyl' is simply another systematic name for benzene, a ring of #C_6H_6# with delocalised electrons. 'Phenol' is the alcohol form of benzene, because it has an #-OH# or hydroxyl group.

Jacob Anderson · Answer

undefined A phenoxide ion is the conjugate base of a phenol compound, formed by removing a hydrogen ion (proton) from the hydroxyl group (-OH) attached to a benzene ring. It is represented by the formula C6H5O^-.