1,3-Butadiene Orbital Energy and Nodes

1,3-Butadiene shows how conjugated dienes gain stability through π molecular orbitals. Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, so they are more stable. The simplest conjugated diene is 1,3-butadiene, a four-carbon molecule with each carbon sp2-hybridized and each carbon carryin...

1,3-Butadiene is a conjugated system with four sp² hybridized carbons, each with an unhybridized p orbital containing one electron.

A linear combination of the four unhybridized atomic p orbitals gives rise to four π molecular orbitals, two bonding and two antibonding.

The four π electrons occu...