Science question, really fast.

Quick question about science.

What is the most common form of Nitrogen-Oxygen compound. And if it helps, the ones formed in the sky, and the reason for the northern lights.

Please give the formula as well*.

*By formula, I mean compound formula. Aluminum and Oxygen make Aluminum Oxide… damn, I don’t know the chemical abbr. for the element… like NO2, or O2, or AlO6, or whatever.

Thanks in advance.

As for the NO question, I don’t know. I’d suspect NO2 or NO3, but that’d be a guess and nothing more.

Thanks Sin. But it’s too late. I already guessed at Nitric Oxide, NO2.