Silicon - a fantastic element

Silicon collage

Silicon occurs in enormous quantities in the form of quartz and in its solid state it is the most common element in the earth's crust. 

Quartz consists of silicon and oxygen, and if you want the silicon you have to separate it from the oxygen, as well as remove other substances and impurities.

Silicon is not a metal
. Silicon is a semiconductor, which means that silicon does not conduct electricity at room temperature, only when it is heated up. Its conductance can be adjusted using phosphorus and boron. This has made silicon a vital component of all electronics, where electrons in circuit need to be turned on and off.

Silicon is everyone's friend. It is easy to combine silicon with other elements, which means it can help to create new, practical substances. The most common use of silicon is to mix it in with aluminium. Silicon makes aluminium stronger and more pliable, and enables cars, aeroplanes and other means of transport to be built using light aluminium instead of heavy metal. This means they also use less energy. Thanks to silicon, aluminium can be re-smelted and reused almost indefinitely. Half of all the silicon that is produced is mixed with aluminium.

Silicon can be both rubber and stone. Silicon can be transformed into silicone, which is a synthetic substance formed by silicon reacting with methyl chloride. This results in a new substance, dimethyldichlorosilane, which can be imbued with a number of practical properties by changing its molecular chain's length and composition. We are familiar with it from rubber-like products such as draught strips, dummies for babies, and cables, but it is also used in water-based paints, make-up and a number of other products. Around 30% of the silicon produced is used in silicone production. 

Silicon has a high melting point. With a melting point of 1,414oC, silicon is a very suitable replacement for asbestos and is used in a number of ceramic products. Porsches, Ferraris and top-of-the-range Audis use ceramic braking pads because they are lighter and generate less heat. Silicon is also used in diesel filters in cars and construction machines to remove NOx from exhaust gases.

Silicon + sun = electricity. The electrons in the nucleus of a silicon atom easily achieve a higher level of energy (they excite) when the sun shines on it, meaning that an electron is released and a wave occurs (electricity) that can be caught and results in electrical tension. The amount of silicon that is used in solar cell production via polysilicon (super pure silicone) has increased from 1 per cent a few years ago to 10 per cent today, and the solar cell industry appears to continue to grow rapidly.

Silicon is water-repellent. This property is exploited when, for example, silicon dust (microsilica) is used in concrete. This enables large structures, such as bridges and skyscrapers, to be built safely and last longer using smaller amounts of materials. Silicon dust is really a by-product of silicon production and was previously regarded as waste.