combustion - Is oxygen necessary for burning?

Is oxygen really necessary for burning things?

What if there was no oxygen around? Would there still be a way to burn things?

Answer

Yes, absolutely. Burning refers to oxidation accompanied by a flame and there are numerous reactions in which oxygen takes no part. Most of these are either with elementary halogens, or compounds thereof.

Here are some examples.

$$\begin{align} \ce{2K + F2 &-> 2KF}\\ \ce{2Fe_\text{wool} + 3Cl2 &-> 2FeCl3}\\ \ce{H2O + ClF3 &-> HF + HCl + OF2}\\ \ce{2H2O + ClF3 &-> 3HF + HCl + O2}\\ \ce{2Cl2 + 2OF2 &-> 4ClF + O2} \end{align}$$

So in fluorine chemistry, you don't oxygenise it; it flourises you.