Crystd from acetone or cyclohexane, sublimed in a vacuum below its melting point.

(CAS NO. ) was also purified by dissolving in n-heptane (ca l0ml/g of adamantane) on a hot plate, adding activated charcoal (2g/100g of adamantane), and boiling for 30min, filtering the hot soln through a filter paper, concentrating the filtrate until crystn just starts, adding one quarter of the original volume n-heptane and allowing to cool slowly over a period of hours. The supernatant was decanted off and the crystals were dried on a vacuum line at room temperature.