Atmospheric photochemistry: roaming in the dark.

for the conversion of dinitrogen into ammonia, by demonstrating that ammonia is directly obtained from the nitrido species. The reactivity of the transitionmetal–nitrido complexes described in their papers shows a real advance towards developing a ‘post-Haber–Bosch process’: a synthetic method for the catalytic formation of ammonia from molecular dinitrogen under mild reaction conditions. These papers provide essential information for developing a catalytic nitrogen-fixation system by using iron catalysts7. ❐