Element

Silicon Element Properties and Information

Published August 16, 2023 · Updated August 11, 2023

Silicon

Silicon Element Properties and Information:

Silicon is fourteenth element on the periodic table. Elements are arranged in the periodic table on the basis of the atomic number. Atomic number is the number of protons in the nucleus of the atom. Silicon has an atomic number of 14. It is located in the Group 14 and Period 3 of the periodic table of elements. It is denoted by Si. The name is derived from the Latin word ‘Silicis’ meaning Flint.

Jöns Jacob Berzelius is credited to be the first person to obtain silicon by heating potassium fluorosilicate with potassium in 1824. The material obtained was contaminated with potassium silicide, it was stirred with water which yielded relatively pure elemental silicon after reaction.

Silicon is the second most abundant element on earth’s crust after oxygen. It makes up to about 27.7% of the earth’s crust by mass. Silicon occurs in nature only in combined form and primarily it occurs in the form of oxides and silicates.

Physical Properties:

Ultrapure silicon is a solid with blue-grey metallic sheen.
The atomic mass of silicon is 28.085
The melting point of silicon is 1410°C
The boiling point of silicon is 3265°C
The density of silicon is 2330 in S.I. units at 20°C
Silicon has three stable isotopes; silicon-28, silicon-29 and silicon-30. Among them silicon-28 constitutes about 92.23% of total silicon.
Silicon is a semiconductor. Its resistivity drops as the temperature rises.

Chemical Properties:

Crystalline bulk silicone is relatively inert but it is reactive at high temperatures.
Silicon forms a thin continuous layer of oxide when exposed to air which protects it from oxidation.
Silicon is vulnerable to nitrogen, phosphorus, fluorine at high temperatures. Silicon gets attacked by halogens even when it is protected by the oxide layer.
Alkali and alkaline earth metals react with silicon or silicon dioxide to form silicides.
Silicon forms silanes which are a homologous series of silicon hydrides having similar structural formula as alkanes. Silanes are very strong reducing agents.

Methods of Production:

Carbothermal reduction: Extremely high purity silicon is prepared commercially by carbothermal reduction of silicon dioxide. Sand is reduced with highly pure coke in an electric arc furnace. Excess of silicon dioxide is used in order to stop the silicon carbide from accumulating.
Reduction of tetrachlorosilane: Tetrachlorosilane or silicon tetrachloride is made by chlorinating scrap silicon. It is purified by repeated fractional distillation and then the reduction to silicon metal is carried out using pure zinc metal as a reducing agent. The pieces of silicon obtained are melted then crystallised and zone refined.

Relevance in Chemical and Related Industries:

Cement industries: Silicates are used to make Portland cement which are used in building mortar and stucco. The cement is usually mixed with silica sand and gravel to form concrete which are basis for large infrastructures.
Ceramic industries: Silica are used to make firebrick ceramics, they are used in whiteware ceramics, various types of clays, porcelains, glass and glass fibres.

Relevance in Other Industries:

Semiconductor industry: Silicon is very popular material for high powered superconductors and also integrated circuits because it can withstand high temperatures and greatest electrical activities without breaking down. Also, the insulating oxide of silicon is insoluble in water. The efficiency of the silicon semiconductor increased when it is doped with certain impurities.

Health Effects on Exposure:

Inhalation: Inhalation of silica materials at work place in small quantities may lead to irritation but large concentrations over prolonged period of time causes a disease named silicosis. Silicosis is an occupational lung disease which is marked by inflammation and scarring in the form of nodular lesions in the upper lobe of lungs. Exposure can also cause emphysema and also lung cancer.