Here's why:

* Structure: Sulfur is a non-metal and exists in a crystalline structure. The atoms are held together by weak van der Waals forces.

* Electrons: Unlike metals, the electrons in sulfur are tightly bound to the atoms and cannot move freely. This limits their ability to transfer heat energy.

* Thermal Conductivity: Sulfur has a very low thermal conductivity, meaning it conducts heat poorly.

In contrast, metals are good conductors of heat because their electrons are free to move and carry thermal energy throughout the material.