Silicon vs Silica vs Silicone
It is a common misconception that silicon, silica and silicone are the same. While their names sound similar, all three are quite different. This article describes the properties of each material to give a better understanding of silicon vs silica vs silicone.
Silicon is one of the 97 elements that form all the minerals on Earth. It is the second most abundant element, making up about 28% of the earth’s crust. Silicon is represented by the symbol Si, and its atomic number is 14.
Bluish-grey and metallic in appearance, it is a hard semiconductor and tetravalent metalloid. Silicon is brittle and has a crystalline structure with a boiling point of 3265°C and a melting point of 1414°C.
There are fourteen electrons in an atom of silicon. In the ground state, silicon’s electron configuration is 1s22s22p63s23p2, commonly expressed as [Ne] 3s² 3p² . Four of these are valence electrons occupying both 3p orbitals and the single 3s orbital.
Silicon readily reacts with oxygen to create silicates. Some common silicates are olivine, quartz, mica, jadeite, feldspars, thomsonite and prehnite. Due to the abundance of oxygen in the earth’s crust, it is rare to find silicon in its pure form.
Silicon carbides, which are silicon compounds, can be helpful as abrasives and materials for high-strength ceramics. Silicon also provides the basis for synthetic polymers known as silicones, which we will discuss later in this article.
The late 20th to early 21st century is commonly known as the Information Age or Digital Age, but it is also termed the Silicon Age. This is a reference to the use of silicon in many essential components of the digital era.
Silicon may be used for several commercial purposes without processing. This includes its use in the production of silica sand, clays, and stone. Silicates are commonly used for stucco and mortar, too. Mixed with gravel and silica sand, they produce the concrete used to make roads and build foundations. Silicon is also useful in manufacturing more delicate products, including white-ware ceramics such as porcelain.
Silicon has many important applications in the electronic industry since it is a good conductor of electricity. Although used in a small portion of semiconductor electronics at less than 10%, the highly purified silicon element is essential to MOS (metal-oxide silicon) transistors.
Silicon is also used in the synthesis of polymers called silicones, one of the substances it is often confused with.
Industries such as aluminium casting, steel refining, and fine chemical producers often use free silicon to make fumed silica.
Integrated chips also use silicon in the most advanced technology, such as cell phones and computers. It is probably the most manufactured device in a large number than any other in the history of technology and sciences. For example, Metal-oxide Silicon Field-Effect Transistors or MOSFET is the most popular and successful silicon device.
Silicon is also an essential element in biology, although animal physiology only requires traces of silicon in their bodies. However, various ocean species, such as sea sponges and microorganisms like radiolaria and diatoms, are known to secrete silica-based skeletal structures. Silica is also known to deposit in various plant tissues.
Common Uses of Silicon
Silicon is used in a wide range of industries. It is an important component in the production of alloys (compounds of metals and non-metals). Silicon is used in the construction industry and high-tech equipment such as computer chips, solar panels and transistors.
Silicon is refined in two stages before it is used in electronic devices. In the first stage, oxygen is removed from the compound. The second stage is a refinement process that produces hyper-pure silicon, a semiconductor-grade element. Hyper-pure silicon is essential for the manufacture of many electronic devices, including circuit boards and microchips.
2. Solar Panels
One of silicon’s most important properties is its ability to function as a semiconductor. Because of this property, silicon is used in producing most solar cells and solar panels. Pure silicon is not used here as it is a poor conductor; instead, silicon is mixed with impurities in a process known as doping to absorb and convert solar energy into electricity.
Silica, or silicon dioxide, is an oxide of silicon with the chemical formula SiO₂. It is mainly found naturally in quartz and diverse living organisms. Silica is one of the significant constituents of sand in many parts of the world. It is one of the most abundant and complex families of materials. The chemical only exists as synthetic products and compounds of various minerals. Notable examples include fumed silica, aerogels, fused Quartz, and Silica Gel.
A silicon atom displays tetrahedral coordination in most silicates, which means four oxygen atoms surround a single silicon atom in the centre. Quartz polymorphs are the most common example of this phenomenon.
A 3D network solid with each silicon atom bond covalently in a tetrahedral fashion to four oxygen atoms. However, molten silica exhibits various peculiar physical behaviour and characteristics similar to those in liquid water. These include density maximum at 5000⁰C temperatures, negative temperature expansion, and heat capacity minimum. Molten silica’s density slides from 2.08 g/cm3 at temperatures of 1950⁰C to 2.03 g/cm3 at increased temperatures of 2200 ⁰C.
Silica is naturally found in some foods and is added to many food products and supplements. It is commonly used as an anti-caking agent in foods and supplements to prevent ingredients from clumping or sticking together. It is sometimes added to liquids and beverages to control foaming and thickness.
How is Silica Gel Made?
Silica gel is commonly used as a desiccant to absorb moisture inside the packaging to protect its contents. The process involves a combination of acid and water glass solution. Timing is vital in the process as the formation of the gels is immediate during the composition. Upon completion, the Silica gel desiccants will be distributed accordingly to their mesh size using layers of mesh screens from the top. The silica gel has to then go through a washing process with ammonia to remove excess salt and then dry them using oven drying.
Find out more about silica gel uses and our video here.
Silica is used in the production of glass. Silica beads are also used in chromatographic applications. Silica has uses in structural materials and as electrical insulators in microelectronics, and one can also find silica as a compound in the pharmaceutical and food industries. While inhaling crystalline silica can be toxic to humans, note that silica gel, which is amorphous, is not crystalline silica. It can harm lung tissue and cause severe inflammation, bronchitis, silicosis, systemic and lung cancer. It can also cause systemic autoimmune diseases such as rheumatoid arthritis and lupus. Crystalline silica is a mineral commonly found in many industrial products at contradiction sites, such as glass, bricks, and artificial stone.
Silica is used as a functional filler in paints, plastics, and rubber, and silica sand is used in water filtration and agriculture. Other common applications include constructing and maintaining a wide range of sports and leisure facilities.
Silicones are a diverse family of speciality, high-performance materials that include reactive silanes, silicone fluids, and silicone polymers. These materials are critical to key sectors of our economy, such as health care, aerospace, personal care, electronics, transportation, and construction.
Silicone, also known as polysiloxane, is a synthetic polymer derived from siloxane. It has a chemical representation of “-R2Si-O-SiR2-,” where R represents the organic group. These are generally colourless, rubber, or oil-like substances. Silicones are a significant element used in adhesives, sealants, lubricants, cooking utensils, medicine, and electrical and thermal insulations in the industry. Common silicone forms include silicone grease, silicone resin, silicone oil, silicone rubber, and silicone caulk.
The more precise term to define silicone is polymerised siloxanes. It has a backbone chain consisting of an inorganic silicon-oxygen atom bond (⋯–Si–O–Si–O–Si–O–⋯). Each silicon centre has two organic groups attached to it. These organic groups are commonly methyl. The materials can either be polymeric or cyclic. Silicone can be synthesised with various compositions and properties by varying the backbone chain length, crosslinking, and side groups. Silicones come in a variety of consistencies, from gel to liquid to hard plastic to rubber. Linear PDMS, or polydimethylsiloxane, which is silicone oil, is the most common siloxane. Interestingly, based on Wikipedia, the second largest silicone material group is silicone resins based. The formulation is due to cage-like and branched oligosiloxanes.
Silicones are a common component of many products. Some of the most significant categories for silicone applications are as follows:
- electrical for insulation
- electronic for coatings
- Household items such as sealants and cooking utensils, etc
- Automobiles such as gaskets
- Seals in airplanes
- Keyboard pads in office machines
- Tooth impression moulds and other medicine and dentistry industries
- Coatings in paper and textiles
Benefits of Silicone
Silicones provide several advantages to the products in which they are used, including increased flexibility and resistance to moisture, heat, cold, and ultraviolet radiation. Silicones are available in a variety of forms, including solids, liquids, semi-viscous pastes, greases, oils, and rubber. The following are some daily uses of Silicone.
- Personal Care Items
Silicones found in personal care products help to reduce the white residue and tacky feel of antiperspirants and deodorants. They are also “long-lasting,” helping to retain the colour and glossiness of cosmetics, shampoos, and conditioners. Silicones also help to impart better shine, which allows skincare products to be made with higher SPF. Cosmetics, lotions, sunscreens, and cleansers can be applied smoothly and evenly thanks to their wetting and spreading properties.
Silicone increases the efficiency, durability, and performance of solar panels and photovoltaic devices, helping to reduce their cost. Silicones are ideal materials for solar panels and photovoltaic applications because they can withstand the sun for years.
Silicones are used to make keypads, keyboards, copier rollers, and many components of computers, mobile electronics, and home entertainment equipment. Silicones are also important in enabling LED lighting technology. Silicones’ high thermal stability and excellent dielectric properties allow them to be used in a wide range of electrical transmission applications.
- Kitchen Appliances
Silicone bakeware and cookware have a flexible, nonstick surface that is easy to clean and does not impart flavour or odour to food. Cake pans, muffin tins, and baking mats can be transferred from the freezer to the oven, microwave, or dishwasher without affecting the taste or quality of the food.
- Apparel and Sporting Goods
Silicones keep water out of goggles and diving masks. Silicones enable new techniques for designing sportswear that is lightweight, durable, water-repellent, and high performing while still allowing the fabric to “breathe.”
In conclusion, though Silicon, Silica, and Silicone sound and have similar spelling, they are vastly different from one another in terms of their properties and uses.