Sulfur

Sulfur is the non-metallic chemical element of atomic number 16. It has a symbol of S, an atomic weight of 32.07, and a specific gravity of 2.07 (rhombic form) or 1.96 (monoclimic form). Sulfur boils at 832.5°F (444.7°C) and consists of four stable isotopes of mass numbers 32 (95.0%), 33 (0.75%), 34 (4.2%) and 36 (0.015%). Sulfur atoms found in different locations have slightly different percentages of the four isotopes, however.

Sulfur is a bright yellow solid that can exist in many allotropic forms with slightly different melting points, all around 239°F (115°C). The two main forms are called rhombic sulfur and monoclinic sulfur. There is also a rubbery, non-crystalline form, called plastic or amorphous—without shape—sulfur. An ancient name for sulfur is brimstone, meaning "burning stone." It does indeed burn in air with a blue flame, producing sulfur dioxide:

Sulfur itself has no odor at all, but it has a bad reputation because it makes many smelly compounds. Sulfur dioxide is one of them; it has a sharp, choking, suffocating effect on the unfortunate breather. The "fire and brimstone" of the Bible was one of the worst punishments that its authors could think of. The fact that sulfur comes from deep under the ground and that sulfur dioxide can be smelled in the fumes of volcanoes further fueled people's imaginations of what Hell must be like.