Sulfur

Sulfur or sulphur is one of the most reactive elements present in the periodic table. It is a non-metal that belongs to group 16 (VI A) of the periodic table. The atomic number of this chemical element is 16 and is symbolically denoted as S. At room temperature; the elemental sulphur is a crystalline solid with bright yellow colour. The sulfur element is abundantly present in the universe. People have been using sulfur since early times. Historically, people called it brimstone which means burning stone.  

Sulfur Element

Sulphur Atomic Number

16

Group

Group 16 (VI A)

Element category

Non-metal

Block

p-block

Period

3

Atomic Mass

32.066

Electronic configuration

1s22s22p63s23p4

Oxidation States

-2, +4, +6

 

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The above image shows the detailed electronic configuration chart of sulfur.

Natural Occurrence

Sulfur or sulphur is the tenth common element of this universe. The creation of 32S takes place in the massive stars where the temperature is more than 2.5 X 109K. It is also present in many types of meteorites in the form of sulfide. The Jupiter moon lo has distinctive colours due to the presence of a sulfur element in several ways in a molten, gaseous and solid-state. On Earth, sulphur is the fifth common element by mass. Elemental sulfur is generally obtained near the volcanic regions as well as hot springs. In previous times, the primary source of sulphur was Sicily. The submarine volcanoes also lead to the formation of lakes of molten sulphur that is mostly present on the seafloor.

The action of anaerobic bacteria on sulfate minerals like gypsum also leads to the synthesis of native sulfur. Earlier, the commercial production took place by the fossil-based sulfur deposits from gypsum in salt domes. However, this process is currently not the primary source to obtain sulfur for commercial use. Many valuable metal ores like galena, blende, and gypsum are the compounds of sulfur. It is present in the ores in the form of sulfides or sulfates. Natural gas, petroleum and coal also contain sulfur compounds.

Physical Properties of Sulphur

Sulfur or sulphur can form various polyatomic molecules. S8 or octa-sulfur is one of the most popular molecules of sulfur. It is a soft solid that is odourless and has a bright yellow colour. The melting point of this molecule is 115.21 oC, and it boils at 444.6 oC. When this molecule resides between its melting and boiling temperature, it polymerizes which lead to increased viscosity but a lower density. At higher temperatures, the depolymerization occurs, which leads to decreased viscosity.

The density of the sulfur element is around 2g/cm3, which may be lower or higher depending on the allotrope. All the stable allotropes of sulfur don’t allow the electricity to pass through them. Hence, they are great electric insulators.

Chemical Properties of Sulphur

The burning of sulfur produces a blue flame and an irritating odour due to the formation of sulfur dioxide. Sulfur is insoluble in water but partially soluble in non-polar organic solvents, including benzene. The first ionization energy of this element is 999.6KJ/mol, and the second is 2252KJ/mol. The most common oxidation states of this element are +4 and +6. Sulfur is highly reactive and almost reacts with all elements even with the iridium (unreactive metal) except noble gases.

Sulfur compounds have many unusual features as they can exhibit catenation similar to carbon. These properties of sulphur allow it to form chain structures as well as a ring system like the carbon. Hydrogen sulfide (H2S) is one of the most familiar compounds of the sulfur. It is a colourless and poisonous gas that has the odour of rotten eggs. It is naturally present in the form of vapours in mineral water and volcanoes. During the removal of sulfur from petroleum, a large amount of hydrogen sulfide is obtained.

Oxygen and sulfur also combine to form various compounds. The most known oxide of sulfur is sulfur dioxide which is a poisonous and colourless gas. It is also used as a reducing agent and bleach in several industries. Scientists also used it to obtain sulfur trioxide. This oxide is also beneficial in fruit ripening and food preservation.

Uses of Sulphur

There are several uses of sulphur. Some of the popular ones are as follows:

  • Sulfur is an essential element for producing other essential chemicals. The most important chemical produced by sulfur is sulfuric acid which has many industrial applications.

  • The reaction of sulfur with methane gives carbon disulfide, which is essential for manufacturing rayon and cellophane.

  • Vulcanization of rubber is another important use of the sulfur element.

  • Sulfur is one of the crucial components of fertilizers. It is mostly present in fertilizers in the form of a mineral calcium sulfate.

  • Many pharmaceutical products contain organosulfur compounds. It is also a component in many agrochemicals and dyestuff.

  • People are using elemental sulfur as pesticides and fungicides from previous times. Dusting sulfur (sulfur in powdered form) is a common pesticide in organic farming.

FAQ (Frequently Asked Questions)

1. What is the Biological Role of Sulphur?

Every living cell contains sulphur as an essential component. It is present in the human body equal in abundance to potassium. A person who has 70 Kg weight contains around 140gms of S. In different plants and animals, most of the sulphur is present in the form of amino acids. Eggs are high in sulphur content to nourish feathers in chicks. The odour of the rotting eggs is due to the formation of hydrogen sulphide. In the cells, the function of the sulfur is to reduce the hydrogen and its electrons to promote cellular repair.

2. What are the Isotopes of Sulphur?

Sulphur has 36 isotopes in which only four are stable, that is 32S, 33S, 34S, and 36S. The radioactive isotopes of this element have a small half-life of around less than 3 hours. Researchers use sulphur with distinctive isotopic composition to identify sources of pollution. In hydrologic studies, enriched sulphur is used as a tracer. Isotopes of sulphur have various medical applications too. Both 33S and 34S are useful in genome research. 32S is an essential component in the production of radioisotope 32P that has therapeutic applications. 34S is used for the production of medical radioisotope 34Cl, which has many medical applications.