First of all, before everyone tells me to use the search bar, I know that this has been suggested. I am not just suggesting a more powerful version of rubidium. I am suggesting a new element that might be useful.

It would be called RADI, like rubidium, when exposed to water it would explode, but with a lot more pressure and less fire than rubidium, I'd say like around 30-40 pressure with 200 degree flames (I'm not totally sure about the numbers). RADI would, when exposed to neutrons or photons, give out photons and neutrons before being destroyed.

Edit: sorry, I forgot to say that it's a solid. And it's uses would be for an extra powerful explosive and as another radioactive element to put in nukes. It could also be used in reactors.
Please no flaming...

sorry, I was up late last night and forgot to say the uses.

I suggested such a high pressure as all the new players want a bigger explosive, and that's what this would be essentially, with some added qualities.