the unsubstituted diketones. Agreement between experimental and calculated dipole moments is fairly good thus rendering Molecular Mechanics a safe tool for the conformationalanalysis of the title molecules. The most populated conformations have been evaluated for nine ϱ-diketones bearing 1- and 2- adamantyl, tert-butyl, cyclohexyl, 1-phenylethyl and benzhydryl groups as well as two methyl groups and