Ammonia ( NH3 ) is a toxic colorless gas with a pungent smell. Ammonia condenses to a liquid at -33.3 °C (−107.91 °F).
In refining the most common form of ammonia used is ammonium hydroxide, ammonia dissolved in water (household ammonia).
Never let a metal salt solution with ammonium hydroxide dry up, always acidify when done. If a metal solution with ammonium hydroxide is allowed to dry up, explosive metal fulminates can be produced.