I recently viewed a documentary about my new favorite scientist: Fritz Haber. One of his scientific breakthroughs was the Haber process. It involved hydrogen and nitrogen together with large pressure to create ammonia, nitrogen out of the air. This led to the invention of fertilizer which made it possible for there to be 7 billion people. The following elements would help give others a purpose in powder toy.
Nitrogen [NITG]: Highly combustible gas, cools to form liquid nitrogen. Fuses with hydrogen to make ammonia.
Ammonia* [AMON]: Liquid. Explosive when ignited. Grows yeast, plant, and vine faster than water.
I didn't say it had to be reversible.
GAS + Pressure = OIL
That also sounds pretty cool.
EDIT: I just realized that I planned to have ammonia as a liquid anyways.
You mean using pressure to turn OIL into GAS?