What is sulphur
Sulfur is a nonmetallic element that is also tasteless and odorless. The possible valences for this element are 2, 4, and 6, which can be represented by compounds such as hydrogen sulfide (H2S), sulfur dioxide (SO2), and calcium sulfate (CaSO4), respectively. Pure sulfur is insoluble in water and the most stable variety of sulfur (rhombic sulfur) is a yellow crystalline solid.
The nature of sulfur has been known since prehistoric times. The chemical properties of sulfur and its compounds were discovered at about C.E. 250–300 (because it is flammable, alchemists regarded it as essential to combustion). Late after that gunpowder (a mixture of sulfur, charcoal, and potassium nitrate [KNO3]) was first used for military purposes in China in C.E. 904.