orbital hybridisation

In chemistry, orbital hybridisation (or hybridization) is the concept of mixing atomic orbitals to form new hybrid orbitals (with different energies, shapes, etc., than the component atomic orbitals) suitable for the pairing of electrons to form chemical bonds. It was introduced to explain molecular structures when the valence bond theory failed to correctly predict them.

Hybridization is a theoretical model used to describe the behavior of electrons in molecules, rather than an actual mechanism within atoms. It involves mathematical functions that approximate how orbitals combine to create molecular structures that closely resemble real-world observations. For instance, the base atomic orbitals in carbon, including a spherical s orbital and three p orbitals oriented along the x, y, and z axes at 90-degree angles, do not naturally explain the tetrahedral geometry of methane, which features bond angles of 109.5 degrees. To better represent this, parts of the s and p orbitals are mathematically combined to form new hybrid orbitals, termed \[\ce{sp^{3}}\], because they incorporate characteristics from one s and three p orbitals. These hybrid orbitals achieve orientations that allow for the observed bond angles in methane. While atoms are not aware of these theoretical constructs, the model effectively explains how electrons distribute themselves to minimize repulsion, given their negative charge, while maintaining attraction to the positive nuclei of carbon and hydrogen. This results in a structure that is described as \[\ce{sp^{3}}\] hybridized in methane, reflecting our mathematical approximation rather than the actual conditions within the atom.