Illustrated Glossary of Organic Chemistry

sp² orbital: One of a set of hybrid orbitals produced when one s orbital and two p orbitals are combined mathematically to form three new equivalent orbitals oriented toward the corners of a triangle (hence the designation trigonal planar).

	+		+		+		merge to form		+
s orbital	+	px orbital	+	py orbital	+	pz orbital		three sp2 orbitals	+	pz orbital
								Viewed from above the x-y plane; small back lobes omitted for clarity

In ethylene, the carbon-carbon sigma bond is formed by overlap of one sp² orbital (red) on each carbon atom. The carbon-hydrogen sigma bonds are formed by overlap of a carbon sp² orbital (red) with a hydrogen 1s orbital (blue). Overlap of one p_z orbital (black) on each carbon forms the carbon-carbon pi bond.