Description
Sulphur is the chemical element with atomic number. It is an
abundant, multivalent non-metal. Under normal conditions, sulfur
atoms form cyclic octatomic molecules with chemical formula S8.
Elemental sulfur is a bright yellow crystalline solid when at room
temperature. Chemically, sulfur can react as either an oxidant or
reducing agent. It oxidizes most metals and several nonmetals,
including carbon, which leads to its negative charge in most
organosulfur compounds, but it reduces several strong oxidants,
such as oxygen and fluorine. It is also the lightest element to
easily produce stable exceptions to the octet rule.
In nature, sulfur can be found as the pure element and as sulfide
and sulfate minerals. Elemental sulfur crystals are commonly sought
after by mineral collectors for their brightly colored polyhedron
shapes. Sulphur was considered important enough to receive its own
alchemical symbol. It was needed to make the best quality of black
gunpowder, and the bright yellow powder was hypothesized by
alchemists to contain some of the properties of gold, which they
sought to synthesize from it.
Elemental sulfur was once extracted from salt domes where it
sometimes occurs in nearly pure form, but this method has been
obsolete since the late 20th century. Today, almost all elemental
sulfur is produced as a byproduct of removing sulfur-containing
contaminants from natural gas and petroleum. The element\'s
commercial uses are primarily in fertilizers, because of the
relatively high requirement of plants for it, and in the
manufacture of sulfuric acid, a primary industrial chemical. Other
well-known uses for the element are in matches, insecticides and
fungicides. Many sulfur compounds are odiferous, and the smell of
odorized natural gas, skunk scent, grapefruit, and garlic is due to
sulfur compounds. Hydrogen sulfide produced by living organisms
imparts the characteristic odor to rotting eggs and other
biological processes.
Sulfur is an essential element for all life,
and is widely used in biochemical processes. In metabolic
reactions, sulfur compounds serve as both fuels and respiratory
(oxygen-replacing) materials for simple organisms. Sulfur in
organic form is present in the vitamins biotin and thiamine, the
latter being named for the Greek word for sulfur. Sulfur is an
important part of many enzymes and in antioxidant molecules like
glutathione and thioredoxin. Organically bonded sulfur is a
component of all proteins, as the amino acids cysteine and
methionine. Disulfide bonds are largely responsible for the
mechanical strength and insolubility of the protein keratin, found
in outer skin, hair, and feathers, and the element contributes to
their pungent odor when burned.
