Question

Why is it difficult to react nitrogen with hydrogen?

Answer 1

Because the dinitrogen molecule is a sturdy, robust beast........

Explanation:

The common Lewis representation of the dinitrogen molecule is as `:N-=N:`. The dinitrogen molecule is difficult to oxidize in that its HOMO is prohibitively low in energy, and correspondingly difficult to reduce in that its LUMO is prohibitively high in energy.

And nevertheless, the reaction between dihydrogen and dinitrogen is exothermic. It is only in the past 10-20 years that convincing model systems have been developed that demonstrate dinitrogen fixation at a metal centre.