shape of water molecule with molecular orbital theory

Since the two 2 p orbitals are at right angles to one another, valence bond theory predicts a bent geometry for the water molecule with a bond angle of 90°.

The extended Hückel method, developed by Roald Hoffmann, and other semi-empirical methods can be used to rapidly obtain relative orbital energies, approximate wavefunctions, and degeneracies of molecular orbitals for a wide variety of molecules and extended solids. The valence bond theory of the water molecule describes the two O H bonds as resulting from the overlap of the H 1 s orbitals with the two half-filled 2 p orbitals of the oxygen atom. The molecular geometry and the shape of the water molecule are bent due to the repulsion forces of lone pairs. Molecular geometry is the three-dimensional arrangement of the atoms that constitute a molecule. The oxygen atom in the H2O molecule has sp3 hybridization, and the bond angle of H-O-H is 104.5°. Geometry of the water molecule with values for O-H bond length and for H-O-H bond angle between two bonds. In the Hückel approximation, which can be used to obtain approximate solutions for π molecular orbitals in organic molecules, we simplify the math by taking S=0 and setting H=0 for any p-orbitals that are not adjacent to each other. There are two lone pairs on the Oxygen atom as it doesn’t participate in forming bonds. We can however make some approximations to calculate the energies and wavefunctions numerically. First well look at an MO diagram for water, because its pretty simple and water is very important. In order for a molecule to have a bent structure there has to be a pair of lone electrons. Here we wont really explain these methods, just show some results. Calculating β is not straightforward for multi-electron molecules because we cannot solve the Schrödinger equation analytically for the wavefunctions. The geometric structure of a single water molecule is bent.

Β is an important quantity, because it tells us about the bonding energy of the molecule, and also the difference in energy between bonding and antibonding orbitals.

Shape of water molecule with molecular orbital theory