While they are both made entirely of carbon atoms, the difference in their structure and bonding leads to their vastly different properties.

* Diamond: has a rigid, crystalline structure where each carbon atom is bonded to four others in a tetrahedral arrangement. This creates a very strong and hard material.

* Soot: is amorphous carbon, meaning it lacks a regular, repeating structure. It is made up of tiny particles of carbon that are loosely bonded together. This gives soot its soft, black, and powdery texture.