Alkaline earth exchanged X zeolites are characterized by pyrrole chemisorption using FTIR spectroscopy. Lewis basic, Lewis acidic (cations) and also Bronsted acidic sites were detected in these zeolites. Based on a local environmental model, the charges on oxygens (basic sites) and cations are further calculated using the electronegativity equivalence method. The NH stretching frequencies of pyrrole chemisorbed on both basic and acidic sites are well correlated with these charges. This relationship supports the early idea that the alkaline earth cations in faujasite exist in the form of (MOH)1+.