Molecular geometry plays a crucial role in determining the electronic structure of a molecule. The electronic structure refers to the arrangement of electrons in a molecule, which influences its chemical properties, reactivity, and stability. Molecular orbital theory MOT is a widely used method to describe the electronic structure of molecules by considering the combination of atomic orbitals to form molecular orbitals.The impact of molecular geometry on electronic structure can be understood in the following ways:1. Overlap of atomic orbitals: Molecular geometry determines the spatial arrangement of atoms and their orbitals in a molecule. The extent of overlap between atomic orbitals is directly related to the molecular geometry. Greater overlap leads to the formation of stronger bonds and more stable molecular orbitals.2. Bond angles and bond lengths: Molecular geometry defines the bond angles and bond lengths in a molecule. These parameters affect the energy of molecular orbitals and, consequently, the stability of the molecule. For example, in a bent molecule like water H2O , the bond angle between the hydrogen-oxygen-hydrogen atoms influences the energy of the molecular orbitals and the overall stability of the molecule.3. Electron-electron repulsion: Molecular geometry affects the electron-electron repulsion in a molecule. When electrons are closer to each other due to the molecular geometry, the repulsion between them increases, leading to higher energy molecular orbitals and less stable molecules.To calculate the electronic structure using molecular orbital theory, follow these steps:1. Determine the atomic orbitals of the constituent atoms: Identify the atomic orbitals s, p, d, etc. of the atoms involved in the molecule.2. Combine atomic orbitals to form molecular orbitals: Atomic orbitals combine to form molecular orbitals through a process called linear combination of atomic orbitals LCAO . The number of molecular orbitals formed is equal to the number of atomic orbitals combined. Molecular orbitals can be bonding lower energy and increased stability or antibonding higher energy and decreased stability .3. Apply symmetry considerations: Consider the symmetry of the molecule and its orbitals to determine which atomic orbitals can interact and form molecular orbitals. Orbitals with the same symmetry can combine, while those with different symmetries cannot.4. Determine the energy levels of molecular orbitals: Calculate the energy levels of the molecular orbitals using quantum mechanics and the principles of MOT. Lower energy molecular orbitals are more stable and are filled with electrons before higher energy orbitals.5. Distribute electrons in molecular orbitals: Fill the molecular orbitals with electrons according to the Aufbau principle lowest energy orbitals are filled first , Hund's rule degenerate orbitals are singly occupied before being doubly occupied , and the Pauli exclusion principle each orbital can hold a maximum of two electrons with opposite spins .6. Analyze the electronic structure: The distribution of electrons in molecular orbitals provides information about the molecule's electronic structure, bond order, and stability. Bond order is calculated as number of electrons in bonding orbitals - number of electrons in antibonding orbitals / 2. A higher bond order indicates a stronger bond and a more stable molecule.By following these steps, molecular orbital theory can be used to understand the impact of molecular geometry on the electronic structure of a molecule and predict its properties and reactivity.