Ammonia solution is a solution of ammonia in water. Alternatively, it is known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, liquid ammonia, aqua ammonia, aqueous ammonia, or (inaccurately, nevertheless commonly referred to as) simply ammonia. It can be denoted by the symbols NH3(aq). Although the name ammonium hydroxide suggests a salt with the composition [NH+4][OH−], it is impossible to isolate samples of NH4OH. The ions NH+4 and OH− do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions.