I would say many chemical reactions create radio waves, if you consider light to be very high frequency electromagnetic radiation, that can be easily observed you can see chemical reactions creating 'radio' waves. (at the frequency of visible light).
But I would also assume that EM radiation would proporgate from any material at an excited state.
Also a chemical reaction can produce electricity, that in turn can create a spark and generate RF, but that is more a secondary effect, just as a battery can power a radio transmitter. I sure you did not mean that :)
There are also various chemical die's that will generate light, and it also occures in nature, (I found some Fungi when camping once that glowed in the dark).
They create chemical luminescense, and light is radio waves that you can easily see.
So those reactions will probaby also be generating frequencies lower that visible.