for conformational analysis. Relative stabilities and/or enthalpies of hydrogenation of cis- and trans-monoölefins, diolefins and acetylenes derived from 1,1,4,4-tetramethylcyclodecane have been determined. Large differences were found in the stabilities and enthalpies of hydrogenation between position isomers in each of the three classes of compounds. The results are discussed in conformational terms