Ammonia liquor, also known as ammonium hydroxide, ammonia water, ammonical liquor, ammonia solution, aqua ammonia, aqueous ammonia, or simply ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests a base with composition [NH4+][OH−], it is actually impossible to isolate samples of NH4OH, as these ions do not comprise a significant fraction of the total amount of ammonia except in extremely dilute solutions.