Four zwitterionic compounds of sulfamic acid type: sulfamic acid (SA), aminomethanesulfonic acid (AMA), taurine (TAU), and 3amino1propanesulfonic acid (APA) were selectedFouriertransform infrared spectroscopy (FTIR) was employed to investigate the zwitterionic structures of these compounds The results demonstrate the presence of zwitterionic forms for all four substances, as evidenced by the presence of stretching vibrational peaks for NH3+ and SO3- in the infrared spectra Phase transition temperatures and thermal stability were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) The results indicate that all four zwitterionic compounds undergo melting accompanied by decomposition, with taurine exhibiting the highest thermal stability