Sulphur is an essential element for all life. It is widely used in bio-chemical processes. Sulphur in organic form is present in the vitamins biotin and thiamine, the latter being named for the Greek word for Sulphur. Chemically, Sulphur can react as either an oxidant or reducing agent, which means it gains or loses electrons. It oxidizes most metals and non-metals, including carbon, which leads to its negative charge in most Organo Sulphur compounds. But, it reduces many strong oxidants, such as oxygen and fluorine. In nature, Sulphur can be found as the pure element and as sulfide and sulfate minerals.
What is the History of Sulphur?
Sulphur (Sulvari in Sanskrit and sulphur in Latin) was known in ancient times and is referred to in the Torah (Gensis). Being abundantly available in native form, Sulphur was known in ancient times, mentioned after its uses in ancient Greece, China and Egypt. Sulphur is referenced in the Bible as” Brimstone” giving rise to the name of ‘fire and brimstone’ sermons. In 1777, Antoine Lavoisier helped convince the scientific community that Sulphur was a basic element, rather than a compound. In 21st century, almost all elemental Sulphur is produced as a by-product of removing Sulphur-containing contaminants from natural gas and petroleum. A natural form of Sulphur known as “shiliuhuang” was known in China since the 6th century BC. By the 3rd century, the Chinese discovered that Sulphur could be extracted from pyrite.
What are the Chemical Properties of Sulphur?
Sulphur is an odorless, tasteless, soft, bright-yellow solid. It is a reactive element that given favorable circumstances combines with all other elements except gases, gold and platinum. Sulphur appears in a number of different allotropic modifications. Each allotropic form differs in solubility, specific gravity, crystalline, crystalline arrangement and other physical constants. These various allotropes also can exist together in equilibrium definite proportions, depending on temperature and pressure. It combusts with a blue grow, when exposed to pure oxygen, forming sulphur oxide. The different allotropic modifications of Sulphur are as follows.
Rhombic and Monoclinic Sulphur: The Rhombic structure is the most commonly found Sulphur form. Both rhombic and monoclinic crystalline modifications of Sulphur are made up of 8 Sulphur atoms arranged in a puckered-ring structure. At one atmospheric pressure and temperatures less than 95.4 degree centigrade, rhombic is the stable crystalline form. Above 95.4 degree centigrade, to melt temperature, of 118 degree centigrade, the crystalline monoclinic crystalline structure is dominant. Sulphur is not readily wetted or dissolved by water. Similarly, rhombic and monoclinic Sulphur have limited solubility in natural rubber and synthetic elastomers at room temperature.
Polymeric Sulphur: At 160 degree centigrade and higher, the 8 member ring Sulphur molecule is energized and ruptures. The open chain Sulphur molecule that takes shape combines to make long unbranched polymer chains by a free radical mechanism. The polymeric allotrope of Sulphur is insoluble in organic media, natural, synthetic rubber as well as in carbon-di-sulfide. Due to the insolubility, polymeric Sulphur is referred to as insoluble Sulphur.
What are the Physical properties of Sulphur?
Sulphur or Sulphur is the chemical element with atomic number 16 and atomic mass 32.06 g/mol.
It is represented by symbol S.
It is an abundant, non-metal.
At normal conditions, Sulphur atoms form cyclic octatomic molecules with the chemical formula S8.
Elemental Sulphur is a bright yellow crystalline solid.