Where do Electrons escape from ?
Ferrocene , ( C5H5 ) 2Fe , for the central Fe : neutral counting : Fe contributes 8 electrons , the 2 cyclopentadienyl - rings contribute 5 each : 8 + 2 (5) = 18 electrons ionic counting : Fe2 + contributes 6 electrons , the two aromatic cyclopentadienyl rings contribute 6 each : 6 + 2 (6) = 18 valence electrons on iron .