The reaction of Ammonium Zirconium Carbonate (AZC) with carboxyl groups is really a controlled decomposition.

As water is lost from zirconium carbonates, the molecule becomes unstable and CO₂ is lost. In the case of AZC alone, this would result in the formation of a gel or a precipitate, depending on the concentration.

When AZC is in the presence of carboxylated binders, like starch and latex, a different reaction prevails. As the AZC molecule starts to destabilise, an active zirconium is created, which tries to stabilise itself by reacting with available carboxyl groups. This is depicted in the short video below.

As carbonate groups on different parts of the AZC molecule decompose, more active zirconium sites are created, each of which can co-ordinate with any available carboxyl groups.

When carboxyl groups on different binder molecules interact with different sites on the same AZC chain, crosslinking occurs.