EXPLOSIVES
'(<a href="http://www.j-archive.com/media/2008-10-14_DJ_11.jpg" target="_blank">Jimmy of the Clue Crew holds an explosive brick at the New Mexico Institute of Mining & Technology.</a>) <a href="http://www.j-archive.com/media/2008-10-14_DJ_11a.jpg" target="_blank">This</a> 3-lettered nitrogen compound popular in demolition can be cast in liquid form, because it melts at 178 degrees, but won't explode below 464'
TNT