Ammonia solution
Ammonia solution, also known as ammonia water, ammonium hydroxide, ammoniacal liquor, ammonia liquor, aqua ammonia, aqueous ammonia, or (inaccurately) ammonia, is a solution of ammonia in water. It can be denoted by the symbols NH(aq). Although the name ammonium hydroxide suggests an alkali with composition [NH][OH], it is actually impossible to isolate samples of NHOH. The ions NH and OH do not account for a significant fraction of the total amount of ammonia except in extremely dilute solutions.
Oxide
The oxide ion has the formula O. It is the conjugate base of the hydroxide ion, OH and is encountered in ionic solids such as calcium oxide. O is unstable in aqueous solution − its affinity for H is so great (p"K" ~ −38) that it abstracts a proton from a solvent HO molecule: