Ammonium Nitrate Ammonium Nitrate example essay topic

Ammonium Nitrate Ammonium Nitrate (AN), NH 4 NO 3, has a molecular weight of 80.05. It does not occur in nature. This white crystalline solid was first described in 1659 by Gabber who called it Nit ram flamens because it produced a yellow flame when burned due to traces of sodium in his samples. Today, AN is the most widely produced ammonium compound in the world.

According to the International Fertilizer Development Center, the current production of AN exceeds 4.5 Million Tons per year in North America. It is primarily used as a Nitrogen fertilizer (as High Density Ammonium Nitrate Granules or Prills) and as a component in Blasting Agent formulations (as Low density prills or in emulsions). AN is very hygroscopic, absorbing moisture from the atmosphere at relative humidifies above 59% in the pure form and as one would also expect is very water soluble. AN can form a 65% solution in water at 20 C. The solid can exist in as many as seven different crystalline modifications or phases depending on temperature, pressure and moisture content of the solid. The pure solid melts at 169 C. Chemically, AN is a salt, the result of an acid-base reaction of ammonia and nitric acid. The reaction is highly exothermic with a heat of neutralization of 280 BTU / ld in dilute solution.

The solid has a negative heat of solution (-142 BTU / lb). A classic article describing Ammonium Nitrate is the Miller and Sae man article published in "Industrial and Engineering Chemistry, Vol. 40, No. 1, Jan 1948, pp. 154-160. Crystallographic Data for Ammonium Nitrate Crystal Systems PhaseVIV Crystal SystemOrthorhombicOrthorhombicOrthorhombicTetragonalCubic Space groupPccnPmmnPnmaP 4/mbm Pm 3 m Formula / Unit Cell (Z) 82421 Lattice Parameters a = 7.943 a = 5.745 a = 7.7184 a = 5.7193 a = 4.366 b = 7.972 b = 5.438 b = 5.8447 c = 9.832 c = 4.942 c = 7.1624 c = 4.9326 Measured at (K) 173295318355423 Reference Herrmann, Michael, J., and Engel, Walter, Phase Transitions and Lattice Dynamics of Ammonium Nitrate, Propellants, Explosives, Pyrotechnics 22,143-147 (1997). More recent publications of AN Crystal Phase include Boe yens at. al., S. Afr. Tydskr.

An excellent article on Ammonium Nitrate corrosivity is "Corrosion of carbon Steel in Concentrated Solutions of Ammonium Nitrate by J. Bystriansky and P. Novak presented at the International Congress on Metallic Corrosion in To tonto, June 3-7, 1994. If your interested in Ammonium Nitrate decomposition research, see the article by MacNeil, Zhang, Ber seth and Troller, "Catalytic Decomposition of Ammonium Nitrate in Superheated Aqueous Solutions", in J. Am. Chem. Soc., 1997, vol. 119, pp. 9738-9744. Of course there are literally hundreds of articles available on Ammonium Nitrate decomposition and I will not try to list those here.

I will however try to update this site with references to new articles as they may be published. I would like to thank Dr. Paul Shields for providing the following updated volume and density data derived from XRD analysis. The PdV and dS are given for the polymorphic phase transformations. Better values may be in the literature but I havent found them yet. Phase 1 is Cubic, 2 is tetragonal, 3 is orthorhombic, 4 is orthorhombic (some references call this phase pseudo-tetragonal or pseudo-trigonal), 5 is tetragonal. Phases 6 and 7 have not been sufficiently described to classify.

Dissociation Pressure, Free Energy and Entropy of Dissociation for Ammonium Nitrate Dissociation Pressure, Free Energy and Entropy of Dissociation for Ammonium Nitrate Temp., 0 CDissoc. Press., mmDFdissoc. kcal / mole D Sdissoc. cal/0 C, moleSNH 4 NO 3 at Cal/0 C, moleSNH 4 NO 3 at 250 C cal/0 C, mole 188.23. 2511.2860. 359.236.

3 205.17. 4510.1260. 160.336. 0 215.911. 559.4959. 7 61.135.

9 223.115. 809.0159. 661.836. 1 236.727. 08.1559. 362.735.

9 249.141. 07.4758. 963.836. 1

Bibliography

web ammonium nitrate chemical compound, NH 4 NO 3, that exists as colorless, rhombohedral crystals at room temperature but changes to mono clinic crystals when heated above 32 C. It is extremely soluble in water and soluble in alcohol and liquid ammonia. It is prepared commercially by reaction of nitric acid and ammonia. Major uses are in fertilizers and explosives. For fertilizers it is in the form of small clay-coated pellets. For explosives it is sometimes mixed with other substances, e. g., TNT, so that it is more easily detonated. It is also used in solid-fuel rocket propellants, in pyrotechnics, and in the production of nitrous oxide. web.