(Chemical symbol: S). A pale yellow, odorless, brittle, nonmetallic element found underground either in the solid state or as molten sulfur. Sulfur is insoluble in water but is soluble in carbon disulfide.

Sulfur is an impurity which appears in steel. It is harmful because it produces hot shortness, although it is frequently added to stainless steel to improve machining qualities. Sulfur is also used in gunpowder, in the vulcanization of rubber and in industrial chemicals. Atomic weight, 87.63; melting point, 900°C (1652°F);specific gravity, 2.64.