Modern Alchemy: Detonating Nitrogen Triiodide

with Dr Peter Wothers

  • Embed using YouTube

    Get the embed code

  • Download:
    mp4, wmv, webm

We have contact...

Nitrogen Triiodide is an extremely sensitive explosive compound that, when dry, can be detonated by the lightest of touches or vibrations. For this reason, it should never be contained or transported and we are not aware of any industrial uses.

A quantity of NIwas prepared in the Ri Prep Room before being laid out to dry in the famous Lecture Theatre. This process took over two hours and, due to the extreme shock-sensitivity of the material, we were only able to attempt the reaction on this scale once. The crew were forced to wear ear defenders at all times in case the material spontaneously exploded.  

As Dr Peter Wothers initiates the reaction, the Nitrogen Triiodide detonates incredibly quickly in a fraction of a second to release a purple cloud of iodine vapour into the room.

Peter Wothers explains further:

"To tie in with the theme of the first Christmas Lecture (Air), I wanted to show the rapid production of a gas, but unfortunately almost all gases are colourless.  The rapid production of iodine vapour from NI3 seemed like the perfect solution.  The most amazing thing for me was the delay visible from the slow-mo footage before the force of the explosion really hit me in the chest!"

Devised to promote the 2012 Christmas Lectures, this is one of three large-scale, chemistry demos that were too big (or too dangerous!) to perform in the Ri Lecture Theatre in front of 400 young people.

This experiment was undertaken under the supervision of professionals and should not be replicated. 




Dr Peter Wothers, Andrew Marmery, Dr Sean Thurston
Royal Institution, London
Filmed in:
The Theatre

The Refinery

Collections with this video:
CHRISTMAS LECTURES 2012 - The Modern Alchemist

cc_by-nc-sa License: Creative Commons



Air is a mixture of several elements, mainly nitrogen, and oxygen, and trace amounts of the noble gases. But this wasn't realised for hundreds of years, and this is because you can't see these elements. They're invisible. But there's one element that has such a beautiful colour in the gas phase it was actually named because of this. And it was named by Sir Humphry Davy.

Some experiments and observations on a new substance which becomes a violet-colored gas by heat, by Sir Humphry Davy, January 20, 1814. "A new and very curious substance has recently occupied the attention of chemists of Paris. The substance appears as a vapour of a beautiful violet colour."

Davy notes that when the new substance is exposed to liquid ammonia a black powder is formed which when dry, fulminates by the slightest contact or friction. What he means is, when you touch it, it explodes.

I'm trying to smear some of this rather unpleasant nitrogen triiodide, but it's deeply unpleasant when dried and incredibly unstable. I've just come to check to see how this is doing. The problem is it needs to dry, and it isn't going to work until it's dried. But the longer we leave it, it could go off by itself. So it's very nervous at the moment.





But I felt that force right in my stomach here. That was a good cloud, wasn't it?

So what we've just seen there is the explosive decomposition of nitrogen triiodide into nitrogen gas and well, the purple cloud of iodine vapour. The explosion has sprayed nitrogen triiodide everywhere, so I feel rather sorry for whoever is going to be in the lecture theatre next.


Ha, nothing's happening.

This is quite good though. The suspense is good, isn't it?


Is it going to go? Oh, your reaction is good.


Related Videos

Collections containing this video: