For bi- and trivalent Meq+ (Me = metal) cations of alkaline earth (AE) and rare earth (RE) metals, respectively, the formation of the nonacid MeOH(q-1)+ species and acid H-O-zeo group, where O-zeo is the framework atom, from water adsorbed at the multivalent Meq+(H2O) cation in cationic form zeolites was checked at both isolated cluster (8R or 6R + 4R) and periodic (the mordenite framework) levels. Both approaches demonstrate qualitative differences for the stability of the dissociated water between the two classes of industrial cationic forms if two Al atoms are closely located. The RE forms split water while the AE ones do not, that can be a basis of different proton transfer in the RE zeolites (thermodynamic control) than in the AE forms (kinetic control). The cluster models allow quantitatively explaining nearly equal intensities I-HF similar to I-LF of the high frequency (HF) and low frequency (LF) OH vibrations in the RE forms and lowered I-HF << I-LF in the AE forms, where HF bands are assigned to the Me OH groups in the RE and AE forms, respectively, while LF bands are assigned to the Si O(H)-Al groups. The role of electrostatic terms for water dissociation in the RE and AE forms is discussed.