They propose the existence of a ‘‘unique hydroxyl nest’’ with framework-connected Al-OH as shown in (b) of Scheme 1 in the framework of the ATY zeolites. The formation of this ‘‘unique hydroxyl nest’’ may not be restricted to the one as schematically described in Scheme 1. Vacancies containing two or more framework-connected Al-OH may also be created depending on the desilication degree in the local framework.