The aqueous ethanolysis reactions of the adamantylideneadamantyl halides (2-Cl, 2-Br, and 2-I) exhibit Grunwald-Winstein sensitivity parameters (m) of 0.74 +/- 0.06, 0.90 +/- 0.01, and 0.88 +/- 0.03 for the chloride, bromide, and iodide compounds, respectively. All reaction products are formed with retention of both the ring structure and the stereochemistry of the reaction center. Common-ion rate depressions are observed during the solvolyses of all three of the homoallylic halides, a result that is consistent with these reactions proceeding via a free-solvated homoallylic carbenium ion. The rate of nucleophilic capture of the homoallylic carbenium ion exhibits a Swain-Scott parameter (s) of 0.20 +/-0.01, indicating that these reactions show a low sensitivity to the nature of the nucleophile. From the data it is estimated that the lifetime of the homoallylic carbenium ion (1) in 60:40 v/v EtOH-H2O at 25 degrees C is at least 6.4 x 10(-9) s.