The final "o" of acenaphtho, benzo, naphtho and perylo and the "a" of the monocyclic prefixes cyclopropa, cyclopenta, cyclohepta, etc. are elided before another vowel, as benz(o)
[a] anthracene. In all other cases the final "o" or "a" is retained
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Copyright 1979 IUPAC.] If you need to cite these rules please quote this reference as their source.
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