The notion of hybridization is the intermixing of orbitals of an atom with roughly the same energy to produce exactly comparable orbitals with the same energy, equal forms, and symmetrical orientations in space. Hybrid orbitals or hybridised orbitals are the new equivalent orbitals created. Hybrid orbitals have qualities that are completely different from the original orbitals from which they were created.
Hybridisation requires the following conditions:
(i) The enthalpies of the orbitals involved in hybridization must be only slightly different.
(ii) The orbitals that are being hybridised are usually from the atom’s valence.
(iii) It can happen between orbitals that are totally filled, half-filled, or unoccupied.
Hybridisation’s Most Important Features
1. The energy of the orbitals participating in hybridization should be close to the same.
2. Hybridization occurs when the orbitals of one and the same atom interact.
3. The total number of hybrid orbitals generated is the same as the total number of hybridised orbitals.
4. In terms of shape and energy, the hybrid orbitals are all the same.
5. A hybrid orbital that participates in bond formation must have at least one electron.
6. The hybrid orbitals tend to stay at the maximum distance apart due to electrical repulsions between them.
7. Sigma (s) bonds are formed by the overlap of atomic orbitals.
8. Pi (p) bonds are formed via the sidewise or lateral overlap of atomic orbitals.
Characteristics.
1. The number of initial intermixing orbitals equals the number of hybrid orbitals generated.
2. Hybrid orbitals have no pure characteristic.
3. The hybrid orbitals are similar in shape and energy to the mixing atomic orbitals, but they are not the same.
4. Hybridisation can occur in both half-filled and fully filled orbitals.
5. The orbitals involved in the hybridisation process must have the same or similar energies.
Atomic orbitals with equal energies undergo hybridisation
In the localised valence bonding theory, hybridization is a mathematical method in which atomic orbitals that are similar in energy but not equal are combined to generate sets of equivalent orbitals that are suitably oriented to form bonds.
Hybridisation of s and p Orbitals
By combining the beryllium 2s orbital with any of the three degenerate 2p orbitals in BeH2, we can make two equivalent orbitals. By adding and subtracting the Be 2s and 2pz atomic orbitals.
What are the conditions for hybridisation of atomic orbitals?
Hybridised atomic orbitals should all come from the same atom or ion.
The energy of the atomic orbitals involved in hybridization should be close to the same. As a result, 2s and 2p can hybridise, as can 3s and 3p, but 2s and 3p cannot. The number of hybrid orbitals formed is equal to the number of mixed atomic orbitals. A set of hybrid orbitals is created by combining atomic orbitals. A set of hybrid orbitals has the same number of atomic orbitals as the number of atomic orbitals used to construct it. All orbitals in a set of hybrid orbitals have the same shape and energy. The sort of hybrid orbitals formed in a bonded atom is dictated by the electron-pair geometry, according to the VSEPR theory.
Hybridisation basic shapes
Linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral hybridization forms are the most common.
The orbital arrangement’s geometry is as follows:
Linear: There are two electron groups involved, resulting in sp hybridization, with an angle of 180° between the orbitals.
Trigonal planar: There are three electron groups involved, resulting in sp2 hybridization and a 120° angle between the orbitals.
Tetrahedral: Four electron groups are engaged, resulting in sp3 hybridization with a 109.5° angle between orbitals.
Trigonal bipyramidal: Five electron groups are involved, resulting in sp3d hybridization, with a 90° to 120° angle between the orbitals.
Octahedral: There are six electron groups involved in sp3d2 hybridization, with a 90° angle between the orbitals.
Examples of Hybridisation
1. Methane (CH4): During the synthesis of the methane molecule, the carbon atom experiences sp3 hybridization in the excited state by combining one ‘2s’ and three 2p orbitals to produce four half-filled sp3 hybrid orbitals in space around the carbon atom, which are orientated in tetrahedral symmetry.
2. The atomic s- and p-orbitals in boron’s outer shell combine to generate three equivalent sp2 hybrid orbitals, allowing it to connect with three fluoride atoms in boron trifluoride (BF3). One sigma and one pi bond form a double bond between carbons in an ethene molecule.
3. Both carbons of ethane (CH3–CH3) are sp3-hybridised, which means they have four bonds with tetrahedral geometry. To create a carbon-carbon bond, an sp3 orbital of one carbon atom overlaps end to end with an sp3 orbital of the second carbon atom.
4. In the IF7 molecule, the hybridisation is sp3d3. There are 7 bond pairs of electrons and 0 lone pairs of electrons in the core I atom. The molecular geometry is bipyramidal pentagonal.
Conclusion
Hybridisation is the process of combining two single-stranded DNA or RNA molecules into a single double-stranded molecule utilising base pairing.