It seems likely the would-be terrorists don't know much about chemistry
They may have been snookered about the chemicals they bought thinking they were deadly poison. After all, as one prominent government leader recently declared,
"Today we are the poorest, the most illiterate, the most backward, the most unhealthy, the most un-enlightened, the most deprived, and the weakest of all the human race," he told the delegates.
Of course, that quote was from President Musharraf of Pakistan so it got very little press coverage here. If a Western leader, say Italy's Prime Minister Silvio Berlusconi, said a similar thing, he'd be blasted in the Press.