What is the unsymmetrical hypothetical hydrocarbon radical, CH3.CH2.CH, analogous to ethylidene, and regarded as the type of certain derivatives of propane; -- called also propylidene called?

propidene — The unsymmetrical hypothetical hydrocarbon radical, CH3.CH2.CH, analogous to ethylidene, and regarded as the type of certain derivatives of propane; -- called also propylidene. (Webster's 1913.)

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