Ammonium salts, decompositions, nitrate

Decomposition and Detonation Hazard. Ammonium nitrate is considered a very stable salt, even though ammonium salts of strong acids generally lose ammonia and become slightly acidic on storage. For ammonium nitrate, endothermic dissociation from lowering pH occurs above 169°C. 

Ammoniacal silver oxide is as dangerous as the previous similar compounds. Thus, the clear solution, which is obtained after centrifuging ammoniacal silver oxide leaves a very explosive compound as a residue to which was attributed the AgaN4 formula. It seems that the decomposition of this nitride is inhibited by ammonium salts. A similar situation was created after treating this ammoniacal oxide with silver nitrate until a solid started to precipitate, and this detonated 10 to 14 days after being prepared. It was assumed that this solid was AggNH. 

Heating a mixture of an ammonium salt with a nitrite salt causes a violent explosion on melting [1], owing to formation and decomposition of ammonium nitrite. Salts of other nitrogenous bases behave similarly. Mixtures of ammonium chloride and sodium nitrite are used as commercial explosives [2], Accidental contact of traces of ammonium nitrate with sodium nitrite residues caused wooden decking on a truck to ignite [3],... 

Ammonia is evolved here in the condensation process of melamine to melam whereas the respective ammonium salts are evolved in the case of the hydrobromide and nitrate. Reactions 9 and 9b show that ammonia should be neutralised by pyrosulphuric acid groups. In TG we have found that diammonium pyrosulphate eliminates ammonia above 350 C, with however complete decomposition ... 

Ammonium nitrate alternatively may be prepared by double decomposition reactions of ammonium salt with a nitrate salt e.g., ammonium sulfate and sodium nitrate ... 

The retarding action of ammonia has also been observed in the decomposition of a number of ammonium salts, eg ammonium perchlorate (NH4CIO4) and ammonium nitrate (NH4N03) (Ref 10) ... 

The converse obviously applies to ammonium nitrate explosives, which must not contain any chlorates, since during storage a double exchange reaction may occur resulting in the formation of ammonium chlorate (p. 476, Vol. II), an unstable substance which decomposes spontaneously. A number of patents were taken out between 1880 and 1895, for explosives based on the use of ammonium chlorate or mixtures of ammonium nitrate with potassium or sodium chlorate. Many accidents which occurred through the spontaneous decomposition of these explosives proved the impossibility of using mixtures containing both chlorates and ammonium salts (Hantke [79]). 

Each of the ammonium salts, and even hydroxylammonium nitrate, initiate decomposition in the same fashion—loss of amine. Indeed, ammonium nitrate, perchlorate, and dinitramidate all sublime. 

---