Nomenclature
According to the rules of systematic nomenclature, adamantane should be called tricyclodecane. However, IUPAC recommends using the name "adamantane".
The adamantane molecule is composed of only carbon and hydrogen and has high Td symmetry. Therefore, its 16 hydrogen and 10 carbon atoms can be described by only two sites, which are labeled in the figure as 1 (4 equivalent sites) and 2 (6 equivalent sites).
The closest structural analogs of adamantane are noradamantane and homoadamantane, which respectively contain one less and one more CH2 link than the adamantane.
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