The current study employs the Pulse Thermal Analysis (PTA) method to investigate the adsorption of gaseous methanol onto various forms of aluminium trifluoride drawing special attention to the strongly adsorbing β-AlF 3 and the recently described high-surface (HS) AlF 3 . Simultaneously or subsequently occurring physisorption and chemisorption can be clearly distinguished and partly quantified. BET surface and NH 3 -TPD data will be discussed together with the surface coverage by methanol determined by TA. The extraordinary sorptive properties of HS-AlF 3 are due to acidic sites at the remarkably large surface. The crystalline modifications η-AlF 3 , θ-AlF 3 , and κ-AlF 3 are less-important as they poorly adsorb exhibiting thermogravimetric curves without clearly expressed mass changes. Their surface loading is comparably poor as found for the stable modification α-AlF 3 .