Picric acid sounds like something out of Harry Potter – and it’s original concoction is the stuff of legend. Picric acid was more explosive than TNT.
Johann Rudolf Glauber first proposed pycric acid in 1742. It was first made from animal horn, silk, indigo and a resin using a recipe that looked almost identical to the ingredients necessary to bring Voldemort his body again.
The military caught wind of this chemical and found that it was highly effective in artillery as it was shock proof. Previous explosives like nitroglycerine would sometimes detonate in the artillery barrel which wasn’t a happy ending for anyone. The British, French and Japanese started toying around with it and it formed the basis for the following boomers:
– Explosive D (US)
– Lyddite (GBR)
-Shimose powder (JAP)
– Ecrasite (AUSTRIA)
– Melinite (FRA)
Why was it so dangerous?
Over time water evaporates from the substance leaving crystalline salts behind. These acid crystals are highly volatile and explode readily under friction or a change in temperature. The crystals react with metals and alkaline materials very easily, such as contrete, to form an explosive picrate salt – this particular salt caused booms that were bigger than TNT.
Picric Acid; Image credit to National Institute of Standards and Technology (NIST)
The sensitivity of picrate acids comes from the NO2 groups on the main body (similar to TNT) – under a reaction they combust releasing a significant amount of heat and energy. Here’s a video to see what can happen: