sp2Hybridorbitale

The sp2Hybridorbitale (sp2 hybrid orbital) describes a class of hybrid orbitals formed when one s orbital and two p orbitals on the same atom mix. The result is three equivalent orbitals that lie in a single plane and are oriented about 120 degrees apart. These three sp2Hybridorbitale provide directions for sigma bonding, while one unhybridized p orbital (pz) remains perpendicular to the plane to participate in pi bonding.

In terms of geometry, an atom using sp2Hybridorbitale adopts a trigonal planar arrangement around that atom, with bond angles close to 120 degrees. The unhybridized p orbital allows for pi bonding with adjacent atoms, supporting double bonds and conjugation. This combination explains the structure of many unsaturated molecules, such as alkenes (for example, ethene) where each carbon forms sigma bonds via sp2Hybridorbitale and the C=C pi bond arises from the interaction of unhybridized p orbitals.

Composition and energy-wise, each sp2Hybridorbitale contains about one third s character and two thirds p character. The three hybrids are degenerate in energy and provide three equivalent bonding directions. Sp2Hybridorbitale are commonly discussed in valence bond theory to describe the bonding in molecules with planar or near-planar geometries, such as boron trifluoride (BF3) or the carbon framework of alkenes.

Compared with sp3Hybridorbitale, which form four sigma bonds in a tetrahedral arrangement, sp2Hybridorbitale offer three bonding directions and a perpendicular p orbital for pi interactions. While a useful approximation, the hybridization concept is complemented by molecular orbital descriptions in modern chemistry, which account for delocalization and resonance in real systems.