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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

sp² hybrid orbital

One of three hybrid orbitals made by mixing one s and two p orbitals. They lie in a plane at 120° (trigonal planar), and one p orbital is left unhybridized, perpendicular to that plane, to form a π bond; an atom with steric number 3, or in exactly one π bond, is sp2sp^2.

sp² hybrid orbitals3 sp² hybrid orbitals point away from each other in a trigonal planar arrangement, 120° apart. one unhybridized p orbital, ⊥ to the plane, remains.120°three sp² orbitals · trigonal planarone unhybridized p orbital, ⊥ to the plane, remains

Example

In formaldehyde, HX2C=O\ce{H2C=O}, the C is sp2sp^2: its three hybrids form σ bonds to two H and to O, and its leftover 2p2p overlaps an O 2p2p side-on to make the C=O π bond. Every carbon in a conjugated chain is sp2sp^2.

See alsoHybridizationTrigonal planarπ bond (pi bond)Conjugation