R0—H RC—H R→C-0—H Propanal, an aldehyd Ethanol R-C-R Diethy ketone Propanoic acid 醇 sp 醛和酮sp 羧酸sp2 R→C-0-R 酯sp Ethyl propagate醇 sp3 醛和酮 sp2 羧 酸 sp2 酯 sp2