Reactions of barium hydroxide with ammonium salts are strongly endothermic. Salts of quaternary ammonium cations are known. Purification involves the addition of an aqueous acid such as saturated ammonium chloride solution. Solutions of ammonium chloride are mildly acidic. One method entails treating formaldehyde with ammonium chloride. This was based on reacting paraformaldehyde and ammonium nitrate in acetic anhydride. Ammonotelism is the excretion of ammonia and ammonium ions. Cyanate then hydrolyses to ammonium and carbonate ions. It is an organic salt classified as a quaternary ammonium compound. Urea dissolved in water is in equilibrium with the isomeric ammonium cyanate. Rhenium is most available commercially as salts of perrhenate, including sodium and ammonium perrhenates. Thus, treatment of concentrated solutions of ammonium salts with strong base gives ammonia. The bomb consisted of about of ammonium nitrate and nitromethane. The microbes break down the organic matter into inorganic ammonium and phosphate. Products are produced as their ammonium salts.