Carbonyl Structure length energy ketone C=O bond 1.23A 745 kJ/mol (178 kcal/mol alkene C=C bond 1.34A 611 kJ/mol (146 kcal/mol) Copyright 2010 Pearson Prentice Hall,Inc. Carbon is sp2 hybridized. C-O bond is shorter,stronger,and more polar than C=C bond in alkenes. Chapter 18 3 Chapter 18 3 Carbonyl Structure ▪ Carbon is sp2 hybridized. ▪ C═O bond is shorter, stronger, and more polar than C═C bond in alkenes