This study deals with host-guest interactions in clathrasils. Silica sodalites with enclosed ethyleneglycol (EG), ethanolamine (EA) and ethylenediamine (ED), respectively, were chosen as a basic model system. The inclusion of the stereochemically similar molecules EG, EA and ED in an identical environment leads to drastic changes in the properties of the different silica sodalites. The thermal properties are investigated by differential scanning calorimetry and temperature dependent powder X-ray diffractometry.