ELI5: Explain Like I'm 5

Isonitrile

Okay kiddo, let me explain what isonitrile is. Imagine you have a bunch of building blocks, but instead of just being a simple square or triangle, these blocks have a funny little shape with three arms sticking out in different directions. We call these building blocks "molecules".

One kind of molecule is called an isonitrile. It's made up of a carbon atom (that's one of the arms) connected to a nitrogen atom (that's another arm), and then there's a third arm that can be anything - it might be a hydrogen atom, a carbon atom, or something else entirely.

Now, the really interesting thing about isonitriles is that they have a really strong and distinctive smell. In fact, they used to be called "carbonyl selenide" because they were discovered by a scientist named Liebig who thought he had found a compound containing selenium, but it turned out to be an isonitrile with a very strong smell!

So, to sum it up, an isonitrile is a molecule with three arms - a carbon atom, a nitrogen atom, and a third arm that can be anything. They have a strong and distinctive smell, and they were discovered by accident when a scientist mistook their smell for something else entirely.