amit

i dont think ammonium nitrate is a crappy explosive. its was used in oklahoma city bombings, and and that waxy coatings are indeed to prevent caking of AN. But while googling it i found this link http://www.worldofcoalash.org/2009/ashpdf/a078-taulbee2009.pdf here they are using by products of coal ash to prevent explosion (thats what i have understood from it:embarass:) also on wikipedia its written :"Ammonium nitrate decomposes into gases including oxygen when heated (non-explosive reaction); however, ammonium nitrate can be induced to decompose explosively by detonation." so dont u think "pop" could have been because of that decomposition and oxygen might have to play a role in it?? also i read about the coating many years ago in newspaper there was also mentioned that those granuals can be crushed using the coffe bean grounding machines and then can be used as an explosive.

i've read in a book (unified approach to inorganic chemistry by w potterfield to be exact) that although ammonium nitrate is a powerful explosive (if i remember correctly united states gives granuals of it coated with wax like substance to farmers so that terrorists cant use it) but its very hard to detonate hence its unlikely that in the test tube it was kind of explosion. rather it should be rapid decomposition. nitrates are first choice as explosives as after reaction they form gases loke N2, O2, H2O which are very stable hence highly exothermic. so cant there be formation of N2O in small quantities along with N2 etc which went undetected? hence the small pop...