The 14th periodic table chemical element having an atomic number of 14, silicon (Si) is a metal-like material that looks and weighs similar to aluminium. However, to be precise, it’s a proton heftier than aluminium and has one proton lesser than phosphorus. Silicon is among the seven elements called the metalloids, which are neither metal nor non-metals but possess both the elements’ properties. A silicon atom has 14 protons and 14 electrons, with its outer shell having 4 valence electrons. In its purest form, silicon looks like grayish, metallic-looking crystals. When in amorphous form, it appears like a brown powder.

Pure silicon crystal. Image credit: Flickr
Pure silicon crystal. Image credit: Flickr

Occurrence

Silicon is the second-most abundantly available Earth crust element, after oxygen. In fact, it’s estimated to make up close to 27.6 percent of the Earth crust. This doesn’t mean the naked human eye can see silicon lying around. Silicon is not naturally pure and invariably exists as a compound blended with other elements. For instance, its most common form is silica (silicon dioxide) and silicate. Silica is a primary sand component, but also found in agate, quartz, micas, granite, diorite, talc, asbestos, pyroxenes, olivines, opal and water. Simply put, silicon makes or can be found in everything from synthetics to spacecrafts, and also the human skeletal system.

Crystalline silicon carbide. Image credit: Flickr
Crystalline silicon carbide. Image credit: Flickr

Discovery

Silicon was not considered an element till the 19th century. Since silicon is naturally merged with other natural elements, several scientists tried separating it from the elements but failed. Silicon was first isolated by Jons Jacob Berzelius, a Swedish chemist, in 1824. The current refinement process entails heating carbon with silica (as sand) to derive silicon. Berzelius used potassium instead of carbon to come up with the first silicon crystals.

Silicon Uses

Silicon is used for making a variety of substances.

  • Silicon is used extensively in making alloys for the welding industry. Silicon alloys are corrosion-resistant, which makes them ideal for constructing bridges, large buildings, trains and ships.
  • Silica is the primary glass ingredient. Glass is manufactured by heating silicon sand with carbon at a temperature of close to 4000 degrees F.
  • Silicon when combined with carbon turns into silicon carbide, which can be used in multiple industrial applications: grinding, abrasives, cutting, polishing, body armor, kilns, and also the aerospace industry.
  • Silicon when added to iron as a trace additive makes the metal less brittle and more resilient.
  • Also, silicone, the synthetic material, has silicon as its structural component. This means menstrual cups, oven gloves and breast implants also have silicon.
  • Silicon is also a major ingredient in non-tech creations, such as ceramics, bricks, fiber optics, caulks, greases, lubricants, insecticides, waterproofing and rubber materials.

Silicon as Electronic Chips

No other chemical element is as important to the technology industry as silicon. Why is this so? This is because pure silicon can either be an effective conductor or insulator, which means its electrical conductivity could be altered. Computer chips need precise voltage regulation to manipulate information.

When pure silicon infuses with impurities (other elements) such as phosphorus or boron, the total number of electrons that are part of the mix alter. This is called doping, wherein the silicon’s electrical properties change, making it a semiconductor. In other words, doping leads to unadulterated silicon transforming into a semiconductor by removing or adding few electrons, making the silicon neither a pure electrical conductor nor insulator. In the real world, this means silicon can help create almost any electronic circuit element on integrated circuit (IC) chips, such as transistors, diodes, capacitors, resistors, etc.

Semiconductor silicon. Image credit: Flickr
Semiconductor silicon. Image credit: Flickr

Does this mean there’s no alternative to silicon? Not at all. In fact, silicon is also not the best semiconducting material available. But because it’s readily available everywhere makes it an inexpensive and much feasible option. For instance, much superior transistors can be made with carbon and also germanium. But these materials cannot be bulk manufactured as silicon. This major influence of silicon on the tech industry is probably what led to the Silicon Valley nomenclature.