Water molecular orbital diagram

Figure 6-4. Schematic molecular orbital diagram for water.

If we choose the oxygen 2s orbital for bonding and leave the 2orbital nonbonding (from the symmetry point of view the opposite choice or a mixed orbital would do just as well actually if the two arbitals are close in energy, they mix), the MOs of the water molecule can be constructed as shown in Figure 6-18. These MOs are compared with the calculated contour diagrams of the water molecular orbitals in Figure 6-19. 

FIGURE 4.3. Assembly of the molecular orbital diagram for water C2y point group) using symmetry-adapted orbitals on the ligands and the central atom/ orbitals. 

Figure 1. Photoelectron spectra and assignments for 1,9-dimethylguanine (1,9-Mefi), 3-hydroxytetrahydrofuran(3-OH-THF), and water. Theoretical ionization potentials and molecular orbital diagrams obtained from 3-2IG SCF calculations are also given. Reproduced with permission from ref. 21. Copyright American Chemical Society.

Figure 4.6 shows the assembly of the molecular orbital diagram of a planar AH3 molecule, point group D3h- The H Is orbitals transform as a/ + e, using analogous techniques to those used earlier for water and ammonia. Using equation 4.37, the... 

Figure 1.1 (a) Molecular orbital diagram of ihe water molecule and (b) electronic... 

Figure 6-19. Contour diagrams of the molecular orbitals of water. Computer drawing by Zoltan Varga with Gaussview [24],...

The H-C-H bond angle in methane is 109.5°. The H-O-H bond angle of water is close to this number but the H-S-H bond angle of H2S is near 90°. What does this tell us about the bonding in water and H2S Draw a diagram of the molecular orbitals in H2S. 

To see how this useful procedure works, let us consider the bonds and the molecular orbitals of the water molecule. Fig. 2 shows a Lewis diagram of H2O, with two lines for OH bonds and two pairs of dots for lone pairs of electrons. The point group is C2 and the lone pairs are placed above and below the plane of the molecule. For a discussion of the stereochemistry of lone pairs, the reader should consult the papers by Gillespie >. 

On metal oxides weak hydrogen bond interactions can also evolve. The molecular orbital energy diagram for the gas-phase water molecule alone is shown in Fig. 6.2. 

Fig. 5.10. Molecular-orbital energy-level diagram for the water molecule.

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