Ligand group orbital approach

Chapter 4 Molecular orbital theory the ligand group orbital approach and application to triatomic molecules 107... 

Fig. 4.19 A qualitative MO diagram for the formation of NH3 using the ligand group orbital approach. For clarity, the lines marking degenerate orbital energies are drawn apart. The diagrams on the right-hand side show representations of three of the occupied MOs the orientation of the NH3 molecule in each diagram is the same as in the structure at the bottom of the figure.

Fig. 4.20 The ligand group orbital approach to the bonding in CH4. (a) The 2, 2p, 2py and 2p atomic orbitals of carbon, (b) The four hydrogen H atomic orbitals combine to generate four ligand group orbitals (LGOs).

Fig. 4.24 A partial MO diagram that illustrates the formation of delocalized C—O ir-bonds using the ligand group orbital approach. The CO2 molecule is defined as l5ung on the z axis. The characters of the and 7r MOs are shown in the diagrams at the top of the figure.

Fig. 4. 25 A qualitative, partial MO diagram to illustrate the formation of a delocalized 7r-system in [NO3] a ligand group orbital approach is used. The characters of the 02" and aj MOs are shown in the diagrams at the right-hand side of the figure.

Fig. 4.28 Qualitative, partial MO diagram for the formation of SFg using the ligand group orbital approach with a basis set for sulfur that is composed of the 3 and ip atomic orbitals.

Fig. 4.30 A qualitative MO diagram for the formation of Xep2 using a ligand group orbital approach and illustrating the 3c-2e bonding interaction.

Use a ligand group orbital approach to describe the bonding in [NH4]. Draw schematic representations of each of the bonding MOs. 

Fig. 20.12 An approximate MO diagram for the formation of [MLg]"" (where M is a first row metal) using the ligand group orbital approach the orbitals are shown pictorially in Figure 20.11. The bonding only involves M—L fr-interactions.

Initially, we illustrate the ligand group orbital approach by considering the bonding in a linear triatomic XH2 in which the valence orbitals of X are the 25 and 2p atomic orbitals. Let us orient the H—X—H framework so that it coincides with the z axis as shown in Fig. 5.11. Consider the two I5 atomic orbitals of the two H atoms. Each I5 atomic orbital has two possible phases and, when the two Is orbitals are taken as a group, there are two possible phase combinations. These are called ligand group orbitals... 

---