ZEOLITE

Addition compounds of the type Na 2 O·Al 2 O 3 ·n SiO 2 ·m H 2 O, with calcium sometimes replacing or present with the sodium. The sodium in the zeolite exchanges with calcium in water, making zeolites useful for water softening. The porous structure of zeolites also makes them effective molecular sieves used as gas adsorbents and drying agents. Artificial zeolites are used as ion exchange resins .