Sulfur: Overview

Sulphur is a non-metal element in the sixth main group of the periodic table.
Recognised by its yellow colour, sulphur is brittle in its solid state.
It exists in several allotropic forms. The most common are rhombic sulphur (stable form at room temperature) and monoclinic sulphur (stable form above 96°C).

Sulfur: Extraction and Uses

Sulphur is mainly obtained from underground deposits. It is brought to the surface by the Frasch process which involves melting it with superheated water and forcing it to the surface with air pressure.
Sulphur is largely used in the manufacture of Sulphuric acid (H2SO4), the most extensively used chemical in the industry.
It is also used in the production of sulphur dioxide for the preservation of dried fruits, and in the vulcanisation of rubber.

When burnt in air, sulphur forms sulphur dioxide (SO2), a poisonous gas with a choking smell: S(s) + O2(g) -> SO2(g)
Heated with metals, sulphur forms metal sulphides, such as iron(II) sulphide: Fe(s) + S(s) -> FeS(s)
Sulphur dioxide can be oxidised further to form sulphur trioxide (SO3): 2SO2(g) + O2(g) -> 2SO3(g). This is used in the manufacture of sulphuric acid with the process named contact process.

Sulphur is a poor conductor of both heat and electricity.
It is soluble in carbon disulphide but insoluble in water.
Heated sulphur is viscous and dark in colour. Upon further heating, it becomes a runny liquid which can then transitions to a solid form on cooling.
Sulphur can be tested visually by its yellow colour, or chemically using a flame test (which produces a blue flame).