Reaction intermediate facts for kids

A reaction intermediate is a special kind of molecule that forms for a short time during a chemical reaction. Think of it as a middle step. It's not the starting material (called a reactant), and it's not the final thing you make (the product). Instead, it's something created along the way, before the reaction finishes.

After each small step in a chemical process, an intermediate molecule is usually formed. These molecules often don't last very long because they are quite reactive.

What is a Reaction Intermediate?

An intermediate is a molecule that appears and then disappears during a chemical reaction. It's like a temporary stop on the way from the starting chemicals to the final products.

Intermediate vs. Transition State

It's important not to confuse an intermediate with a transition state. Here's how they are different:

• A transition state is a very unstable point in a reaction. It has the highest energy. It's like being at the very top of a hill, just before rolling down. You can't really "catch" a transition state.
• An intermediate is more stable. It's at a point of lower energy, like a small dip or valley on the way down the hill. Because they are more stable, intermediates can sometimes be found or even separated from the reaction mixture for a short time.

How Intermediates Work

Imagine a simple chemical reaction where two molecules, A and B, combine to make two new molecules, C and D. Sometimes, this doesn't happen in one single step. It might look like this:

A + B → X → C + D

In this example, X is the intermediate. First, A and B react to form X. Then, X reacts to form C and D. The molecule X exists only for a short time during the reaction.

See also

In Spanish: Intermedio de reacción para niños