Ammonia is a colorless gas with a distinct, pungent odor, composed of nitrogen and hydrogen, with the chemical formula NH₃. It is commonly used in fertilizers, cleaning products, and as a refrigerant. In nature, ammonia is produced by the decomposition of organic matter and is a key component in the nitrogen cycle. Due to its high solubility in water, it can form ammonium ions in aqueous solutions, which are important for various biological processes.