Sulfur or sulphur (, see spelling below]]) is the chemical element that has the [[atomic number 16. It is denoted with the symbol S. It is an abundant multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element and as sulfide and sulfate minerals. It is an essential element for life and is found in two amino acids, cysteine and methionine. Its commercial uses are primarily in fertilizers, but it is also widely used in gunpowder, matches, insecticides and fungicides. Elemental sulfur crystals are commonly sought after by mineral collectors for their brightly colored polyhedron shapes. In nonscientific context it can also be referred to as brimstone.

History

English translations of the Bible commonly referred to sulfur as "brimstone", giving rise to the name of 'fire and brimstone' sermons, in which listeners are reminded of the fate of eternal damnation that awaits the unbelieving and unrepentant. It is from this part of the Bible that Hell is implied to "smell of sulfur", although sulfur, in itself, is in fact odorless. The "smell of sulfur" usually refers to either the odor of hydrogen sulfide, e.g. from rotten egg, or of burning sulfur, which produces sulfur dioxide, the smell associated with burnt matches. The smell emanating from raw sulfur originates from a slow oxidation in the presence of air. Hydrogen sulfide is the principal odor of untreated sewage and is one of several smelly sulfur-containing components of flatulance (along with sulfur-containing mercaptans).

Sulfur was known in China since the 6th century BC, in a natural form that the Chinese had called 'brimstone', or shiliuhuang that was found in Hanzhong. By the 3rd century, the Chinese discovered that sulfur could be extracted from pyrite. Chinese Daoists were interested in sulfur's flammability and its reactivity with certain metals, yet its earliest practical uses were found in traditional Chinese medicine. A Song Dynasty military treatise of 1044 AD described different formulas for Chinese gun powder, which is a mixture of potassium nitrate (), carbon, and sulfur. Early alchemists gave sulfur its own alchemical symbol which was a triangle at the top of a cross.

In 1777 Antoine Lavoisier helped convince the scientific community that sulfur was an element and not a compound. In 1867, sulfur was discovered in underground deposits in Louisiana and Texas. The overlying layer of earth was quicksand, prohibiting ordinary mining operations, therefore the Frasch process was used.