Sulfur is a yellow, brittle, nonmetallic solid element with the atomic number 16 and the atomic symbol S. Its atomic weight is 32.066. The sulfur molecule has eight atoms that can arrange themselves in three different forms, or allotropes: rhombic crystals; prism-like needles, or monoclinal crystals; and shapeless, or amorphous, plastic. The pure element has no odor or taste, nor is it poisonous.

Sulfur was discovered during the prehistoric era. When heated, sulfur gives off a penetrating odor that early civilizations associated with evil. The Bible describes wicked cities being punished with fire and "brimstone," or sulfur. During the Middle Ages, alchemists believed that sulfur was the element that gave all other substances their flammability. Although sulfur has been familiar for thousands of years, it was not until the 1770s that Antoine-Laurent Lavoisier identified it as an element when he published his system of chemical nomenclature.

Sulfur is one of...