hyperconjugation, discussed in section 6.7 in connection with the stabilities of substituted alkenes, is the stabilizing interaction of a vacant rho more orbital and a properly oriented c-h sigma orbital nearby (figure 6.14). the more alkyl groups there are on the carbocation, the more possibilities there are for hyperconjugation, and the more stable the carbocation. note in figure 6.14 than an electatic potential map for the tert-butyl carbocation (ch3) 3 c+ , shows a difference between the hydrogens in the plane ofthe carbons and the six hydrogens above and below the plane. the three in-plane hydrogens have their c-h sigma orbital perpendicular to the cation rho orbital, while the out-of-plane hydrogens have thie c-h sigma orbital more nearly parallel. as a result, only the out-of-plane hydrogerns can take part in hyperconjugation, making them more clectron-poor (green) than the electron-rich in-plane hydrogens.