Pentadienyl radical Radical, pentadienyl C 5 H 7      Real, short lived (transient), electronically neutral species. Gram formula weight (molecular mass) = 67.109 Pentadienyl radical is defined with respect to the entities below: The entities below are defined with respect to: Pentadienyl radical Pentadieny FMO (generic) Radical (generic) chemical compound molecule metal molecular science reaction mechanism ionic material acid base geometry reactivity synthesis science knowledge chemistry Lewis