Enthalpies of mixing of furan, methylfuran, tetrahydrofuran (THF), 1,4-dioxane and cyclopentanone with tetrachloroethane (TCE) were determined by microcalorimetry. All the systems were exothermic in nature, showing the following trend : THF > cyclopentanone > 1,4-dioxane > methylfuran > furan. Saturation of the ring led to a marked increase in the energy of intermolecular interaction. This was attributed to the specific interactions between oxygen and the H of TCE, oxygen and the Cl of TCE, and between the CH2 group and the Cl of TCE. This hypothesis was confirmed by a downfield shift in the NMR spectra on addition of TCE to pure THF, 1,4-dioxane and cyclopentanone.