Sulfur (16)

Sulphur (sulfur) is a pale yellow, odorless, brittle solid, which is insoluble in water but soluble in carbon disulphide. Sulphur is essential to life. It is a minor constituent of fats, body fluids, and skeletal minerals.

The spelling of sulphur is "sulfur" in the USA while sulphur is common elsewhere. IUPAC has does not have jurisdiction over language but has decided sulfur is preferred.

Sulphur is found in meteorites, volcanoes, hot springs, and as galena, gypsum, Epsom salts, and barite. It is recovered commercially from "salt domes" along the Gulf Coast of the USA.

Jupiter's moon Io owes its colors to various forms of sulphur. A dark area near the crater Aristarchus on the moon may be a sulphur deposit. Carbon disulphide, hydrogen sulphide, and sulphur dioxide should be handled extremely carefully. Hydrogen sulphide in very small concentrations can be metabolized, but in higher concentrations it can cause death quickly by respiratory paralysis. It is insidious in that it quickly deadens the sense of smell. Sulphur dioxide is a dangerous component in atmospheric air pollution and is one of the factors responsible for acid rain.

•Name: Sulfur
•Symbol: S
•Atomic number: 16
•Atomic weight: 32.065
•Standard state: solid at 298 K
•CAS Registry ID: 7704-34-9
•Group in periodic table: 16
•Group name: Chalcogen
•Period in periodic table: 3
•Block in periodic table: p-block
•Colour: lemon yellow
•Classification: Non-metallic

Historical information

Origin of name: from the Sanskrit word "sulvere" meaning "sulphur"; also from the Latin word "sulphurium" meaning "sulphur." Sulphur was known in ancient times and referred to in Genesis as brimstone. Assyrian texts dated around 700-600 BC refer to it as the "product of the riverside", where deposits could be found. In the 9th century BC, Homer mentioned "pest-averting sulphur". In 424 BC, the tribe of Bootier destroyed a city's walls using a burning mixture of coal, sulphur, and tar.

Around the 12th century, the Chinese, probably, discovered gun powder (a mixture of potassium nitrate, KNO3, carbon, and sulphur).

Sulphur is one of the elements which has an alchemical symbol, a triangle sitting upon a cross. Alchemists knew that mercury can be fixed with sulphur.

Possibly Antoine Lavoisier should be credited with convincing the scientific community that sulphur is an element (around 1777).

Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of some of his studies by assuming that matter is composed of atoms and that all samples of any given compound consist of the same combination of these atoms. Dalton also noted that in series of compounds, the ratios of the masses of the second element that combine with a given weight of the first element can be reduced to small whole numbers (the law of multiple proportions). This was further evidence for atoms. Dalton's theory of atoms was published by Thomas Thomson in the 3rd edition of his System of Chemistry in 1807 and in a paper about strontium oxalates published in the Philosophical Transactions. Dalton published these ideas himself in the following year in the New System of Chemical Philosophy. The symbol used by Dalton for sulphur is a circle quartered by a cross (think the Dark Is Rising, if you've read that book)

Physical properties

•Melting point: 388.36 [or 115.21 °C (239.38 °F)] K
•Boiling point: 717.87 [or 444.72 °C (832.5 °F)] K
•Density of solid: 1960 kg m-3

Orbital properties

•Ground state electron configuration: [Ne].3s2.3p4
•Shell structure: 2.8.6
•Term symbol: 3P2
•Pauling electronegativity: 2.58 (Pauling units)

Isolation

It is not normally necessary to make sulphur in the laboratory as it is so readily available. It is found as the native element in nature and extracted by the Frasch process. This is an interesting process since it means that sulphur can be extracted from underground without mining it. In the Frasch process underground deposits of sulphur are forced to the surface using superheated water and steam (160°C, 16 atmospheres, to melt the sulphur) and compressed air (25 atmospheres). This gives molten sulphur which is allowed to cool in large basins. Purity can reach 99.5%.

This process in energy intensive; commercial success for this operation depends upon suitable geological conditions as well as access to cheap water and energy.

Hydrogen sulphide, H2S, is an important impurity in natural gas which must be removed before the gas is used. This is done by an absorption and regeneration process to concentrate the H2S, followed by a catalytic oxidation (Claus process) using porous catalysts such as Al2O3 or Fe2O3.

8H2S + 4O2 → S8 + 8H2O

Over the years the Claus process has been improved and a modified process can yield 98% recovery.

In the laboratory, sulphur can be purified by recrystallization from solutions in carbon disulphide, CS2. However the resulting crystals are contaminated with solvent, H2S, and SO2. One good way to purify sulphur is to use a quartz heater (700°C) immersed in liquid sulphur. Carbon impurities decompose to form volatile materials of solid carbon, which coat the heater. After a week or so, finishing with a distillation under vacuum, the result is sulphur with a carbon content of about 0.0009%.

Interesting facts about Sulfur:

1. Sulfur is chiefly found near hot springs and volcanoes all over the planet Earth

2. Sulfur in its natural pure form is yellow and crystalline -- mineral collectors seeks out the best polyhedral instances of sulfur for their collections.

3. Sulfur is not soluble in water.

4. The element was spelled with a "-ph-" in the UK and the British Commonwealth until the year 2000 when world-wide organizations in charge of chemical nomenclature proclaimed the official spelling is with an "-f-" instead.

5. Sulfur was known throughout the ancient world all over the globe, being used as medicine in China, Egypt and Greece thousands of years ago to treat ringworm, acne, eczema, psoriasis and scabies.

6. The Christian Bible calls sulfur by the name brimstone, said name used both literally and figuratively in the centuries since.

7. In the esoteric science of alchemy, the predecessor to modern chemistry, the symbol for the element of sulfur is a cross topped by a triangle.

8. Sulfur is a vital component of black gunpowder.

9. Rather than mining raw natural sulfur as was done centuries ago, sulfur is produced today by processing the sulfur-rich contaminants removed from wells drilled for oil and natural gas.

10. Sulfur, being a constituent of the fluids, fats and tissues of living bodies, is essential to life; one of the vitamins, thiamine, is the actual Greek word for sulfur.

11. Sulfur is consistently found in meteorites that have fallen to earth from outer space.

12. Most compounds that contain sulfur have what most people consider a bad odor -- examples are garlic and the natural scent of a skunk. Odorless natural gas is made pungent as a warning mechanism by adding hydrogen sulfide, which has an odor characterized as rotten eggs (H2S also causes the green layer around the yolk in hard boiled eggs).

13. Commercially, sulfur is a primary component of plant fertilizers, and is used in the production of the widely-used industrial chemical sulfuric acid, as well as in fungicides, insecticides and kitchen matches.

14. Animal skin, hair and feathers all contain the protein keratin whose toughness comes primarily from the di-sulfide bonds -- the pungent smell of burnt hair comes from that sulfur contained therein.

15. Sulfur is an important ingredient in the treatment of waste water to make it potable.

16. The countries that export the most sulfur are Canada, Russia and Saudi Arabia; the countries that import the most sulfur are China, Morocco and the USA.

17. One new use for sulfur is sulfur bitumen or sulfur asphalt as an extender for roadway asphalt binder, acting ecologically to minimize the use of petroleum-based products in road building.

18. Sulfur is used in the manufacture of non-ferrous metals, cosmetics, pigments and pharmaceuticals and in the industrial processes of vulcanization of synthetic rubber and steel pickling.

19. Historically, Sicily was a primary source of sulfur for the world as recently as the 19th century.

20. The Pacific "Ring of Fire" contains many sources of sulfur -- large volcanic deposits of sulfur have been mined for years in Japan, Chile and Indonesia.

21. 89% of the sulfur extracted in the world is used to make sulfuric acid