Isomorphic substitution solids characteristics

II. Non-indifferent electrolytes are capable of changing the value of the surface potential, (p0. These electrolytes usually contain ions that are capable of entering the crystal lattice of the solid, e.g. by isomorphic substitution of ions forming the solid phase. The following characteristic cases can be outlined. 

The microporous crystallite of AlPO-n has the following characteristics (1) molecular-sized pore diameter (2) variety of pore structures, some of which are found in other zeolites (3) no inherent acidity, although both acidity and ion-exchange properties can be altered by the isomorphous substitution by aliovalent cations and (4) high thermostability. Among these properties, most interest has focused on new pore structures and solid acidity. However, the high thermal stability of AlPO-n-based molecular sieves has also prompted new research. 

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