The industrial manufacture of NH₃ from N₂ and H₂ is carried out on a huge scale using heterogeneous catalysis, i.e. the reaction between gaseous N₂ and H₂ is carried out over a solid catalyst. 

(a) Construct an MO diagram for N₂ and use the diagram to explain why N₂ is a chemically inert species. 

(b) To what point group does NH₃ belong? 

(c) Using the appropriate character table in Appendix 3, construct a set of ligand group orbitals for a triangular H₃-fragment. Give symmetry labels to the LGOs.

(d) Construct an MO diagram for NH₃ showing the interactions between the N atomic orbitals and the LGOs of the H₃-fragment. Use the MO diagram to determine the N–H bond order and to confirm that NH₃ is diamagnetic.

Data from Appendix 3

Transcribed Image Text:

C₁ A C₂ A B C2v A₁ A₂ B₁ B₂ C3v A₁ A₂ E E 1 E 1 1 E E C₂ 1 -1 C₂ 1 203 1 1 -1 Cs A' A" 30y 1 0 σ₂ (xz) 1 E z, R₂ x, y, Rx, Ry -1 1 1 Th 1 -1 x, y², 2², xy yz, xz ov'(yz) Z R₂ (x, y) (R₁, R₂) x, y, R₂ z, Rz, Ry Z R₂ x, Ry y, R₂ x² + y2², 2² (x² - y², xy) (xz, yz) 2.².2.xy yz, xz 2.².2 xy XZ yz