Hybridisation is a concept in chemistry that involves mixing atomic orbitals to form new hybrid orbitals that are suitable for the pairing of electrons to form chemical bonds in valence bond theory. The original atomic orbitals are similar in energy but not equivalent, and the resulting hybrid orbitals are equivalent in energy to one another and are oriented so that they can form bonds with other atoms. Hybridisation theory is an integral part of organic chemistry, and it helps to predict the shape of molecules, particularly in organic chemistry. There are different types of hybridisation involving s, p, and d orbitals, such as sp, sp2, sp3, sp3d, sp3d2, and sp3d3 hybridisation. The amount of p character or s character, which is decided mainly by orbital hybridisation, can be used to reliably predict molecular properties such as acidity or basicity. Hybridisation occurs only during bond formation, not in a single gaseous atom.