Here's why:

* Structure: Sulfur is a non-metal and exists in various allotropes (different forms). These forms have relatively weak bonds between atoms and a relatively open structure. This means there are fewer free electrons available to carry heat energy.

* Electrons: In contrast to metals, which have freely moving electrons in their structure, sulfur has tightly bound electrons. This makes it difficult for heat energy to transfer through the material.

Comparison:

* Good conductors of heat: Metals like copper, aluminum, and iron.

* Poor conductors of heat: Non-metals like sulfur, rubber, and wood.

Let me know if you have more questions!