Silicon vs Silica vs Silicone: Differences and Applications

Silicon vs Silica vs Silicone: Differences and Applications

Published On: October 11, 2018 Revised On: October 4, 2024

When exploring materials used in various industries, it’s easy to confuse silicon, silica, and silicone due to their similar names. However, these materials have unique properties that make them suited to different applications. Silicon is a chemical element, while silica is a naturally occurring compound found in sand and quartz.

Silicone, in contrast, is a flexible synthetic polymer. Understanding the differences between these materials is essential for selecting the right one for specific purposes in manufacturing, technology, and product development. This article will summarise each material’s composition, properties, and common uses, providing a clear overview of their unique applications across various sectors.

Silicon

Silicon vs Silica vs Silicone

The late 20th to the early 21st century is frequently called the Information Age or Digital Age, but it’s also known as the Silicon Age.

This term alludes to the use of silicon as a semiconductor in many key Digital Age inventions, including microchips for computers and cell phones and the electrical circuits of most electronics.

Silicon is one of the 97 elemental constituents that comprise all of Earth’s minerals. Its chemical symbol is Si, and its atomic number is 14.

Exhibiting a bluish-grey, metallic facade, silicon is a tetravalent metalloid. Because silicon possesses a crystalline structure, it’s brittle in nature even though it has a boiling point of 3265°C and a melting point of 1414°C.

An atom of silicon contains fourteen electrons. In its ground state, silicon’s electron configuration is represented as 1s22s22p63s23p2 or, more commonly, as [Ne] 3s2 3p2. Silicon features four valence electrons that occupy two 3p orbitals and the 3s orbital.

Notably, silicon readily undergoes a chemical reaction with oxygen to yield silicates, which are not to be confused with silica. The resulting silicates include several more commonly occurring minerals, such as olivine, mica, jadeite, feldspars, thomsonite, and prehnite.

Quartz is also a silicate, but due to its purer silica and oxygen composition, it’s also considered a silica. Confusing? We’ll explain more about silica later on. Of course, given the abundance of oxygen in the Earth’s crust, silicon rarely exists naturally in its pure elemental form.

Carbon and silicon can also be combined to produce silicon carbides, a synthetic compound used as an abrasive and high-strength ceramic material. However, silicon is the fundamental element for creating the synthetic polymer, commonly called silicone, which most people are more familiar with. We’ll discuss this in more detail later in this article.

Benefits and Uses of Silicon

While not essential for bodily functions, silicon plays a significant role as a biological element. Many marine organisms, such as sea sponges, radiolaria, and diatoms, secrete silica-based skeletal structures, which are crucial for their survival.

Additionally, silica deposits have been found in various plant tissues, contributing to structural support and resilience. In commercial applications, silicon and silica offer numerous benefits, including:

  • Silicon produces silica sand, clays, and stone.
  • Silicates derived from silicon are used to produce stucco, mortar, and concrete for constructing foundations and roadways.
  • Silicon is used to manufacture intricate products, including white-ware ceramics like porcelain.
  • Silicon plays a pivotal role in synthesising the synthetic polymers known as silicones used in bakeware, utensils, and gadgets, which people usually confuse silicon with.
  • Various industries, such as aluminium casting, steel refining, and fine chemical production, use fumed silica from silicon compounds like silicon tetrachloride.

Role of Silicon in the Electronics

Due to its unique conductive properties, silicon plays a crucial role in the electronics industry. The majority of our most advanced technologies have integrated chips, making microchips one of the most manufactured devices in the history of science and technology.

Of all silicon devices, metal-oxide silicon field-effect transistors (MOSFETs) are the most popular type. The high-purity form of silicon is an indispensable component of these MOS (metal-oxide silicon) transistors and numerous other electronic devices, including microchips and circuit boards.

In order to achieve its pure form, silicon undergoes a two-stage refining process. The initial stage involves the eliminating of oxygen from the compound, followed by shaping it into a cylindrical ingot by being dipped in molten silicon.

It is then generally sliced into wafers. However, in order to be used as a semiconductor, pure silicon also needs to be doped with boron or phosphorus. Doing this is necessary because pure silicon isn’t a good conductor of electricity by itself.

Role of Silicon in Solar Cell Technology

Silicon’s most significant characteristic is its ability to be synthetically turned into an effective semiconductor. Its conductivity also renders pure silicon invaluable in the manufacture of the majority of solar cells and panels, particularly monocrystalline and polycrystalline silicon solar cell panels, which gather and convert sunlight into electricity.

For monocrystalline panels, pure silicon bars made using the Czochralski method are shaped and then sliced into wafers, followed by fabrication into solar cells. For polycrystalline solar cells, scrap pure silicon fragments from the process are cast into ingots and then sliced into wafers. The solar cells generally get encased in an encapsulant, framed in glass, and backed with a waterproof material thereafter.

Silicon vs Silica vs SiliconeSilica

Silica, or silicon dioxide (oxygenated silicon), is a chemical compound with the chemical formula SiO₂. It’s predominantly found naturally in quartz and various living organisms.

Silica is a critical component of naturally occurring and artificial sands and belongs to one of the most extensive and intricate material families. It exists as either compounds of different minerals or a synthetic product like fumed silica, aerogel, fused quartz, and silica gel.

Silica is a 3D network solid in which each silicon atom forms covalent bonds in a tetrahedral configuration with four oxygen atoms. However, molten silica displays various unique physical behaviours and characteristics similar to those observed in liquid water.

These characteristics include maximum density at a temperature of 5000⁰C, negative thermal expansion, and minimum heat capacity. The density of molten silica decreases from 2.08 g/cm3 at a temperature of 1950⁰C to 2.03 g/cm3 at an elevated temperature of 2200⁰C.

Benefits and Uses of Silica

From construction and manufacturing to healthcare and technology, its unique properties—such as durability, heat resistance, and absorbency—make it an essential material for both industrial and everyday use including:

  • To produce glass and silica beads, as well as silica gel crystals for use as desiccants
  • In structural materials and as electrical insulators in microelectronics
  • As a naturally occurring substance in certain foods
  • Added to numerous food products, beverages, liquids, and supplements as an anti-caking agent or to regulate the thickness and foam formation
  • Crystalline silica is commonly found in many industrial products at construction sites, such as glass, bricks, and artificial stone
  • Silica is also a functional filler in paints, plastics, and rubber
  • Silica sand is used for water filtration, agriculture, and the construction of various sports and leisure facilities due to its drainage properties

It is important to note that the inhalation of crystalline silica can be toxic to humans, causing severe lung inflammation, bronchitis, silicosis, systemic cancer, lung cancer, and systemic autoimmune diseases like rheumatoid arthritis and lupus. If silica gel crystals are eaten, they may also cause choking, as they quickly absorb saliva and get lodged in the throat.

The Manufacturing Process of Silica Gel

Silica gel is widely utilised as a desiccant to absorb moisture within packaging and safeguard its contents from dampness, spoilage, and bacterial growth. The silica gel production process involves combining an acid and an alkaline silicate solution like water glass.

This process forms silicic acid, which can be shattered or shaped in a mould or by the process of either spraying or hot pressing. After production, and depending on its purpose, silica gel needs to be washed in water or ammonia to remove sodium solids, and a hot alkaline solution, cobalt chlorine, or another solution to add additional characteristics to it.

Then, it’s heated to remove any remaining moisture – for maximum efficacy as a desiccant, a little water is left in the mixture. Silica gel desiccants are also classified and sorted according to size using a series of mesh screens. Further information on the uses of silica gel and a related video can be accessed through the provided hyperlinks.

Silicone

Silicone, or polysiloxane, is a synthetic polymer composed of repeating units of siloxane. The most common siloxane is linear PDMS, or polydimethylsiloxane, which is silicone oil.

Silicone compounds are typically transparent, rubbery, or oily in composition and are renowned for their rubber-like characteristics, including water resistance and flexibility.

Another term to define silicone is polymerised siloxanes. Silicone has a backbone chain of an inorganic silicon-oxygen atom bond (⋯–Si–O–Si–O–Si–O–⋯). Each silicon centre has two organic groups attached to it, commonly methyl.  , The second-largest silicone material group is silicone resins, formulated from cage-like and branched oligosiloxanes.

Silicon vs Silica vs Silicone

Benefits and Uses of Silicone

Silicones offer several benefits to the products they are incorporated into, including enhanced flexibility and resistance to moisture, heat, cold, and ultraviolet radiation.

As such, these materials play a critical role in various essential sectors of the economy, including healthcare, personal care, aerospace, electronics, transportation, and construction. The following list provides some common products and items formulated using silicone:

  • Several high-performance materials, including silicone fluids, polymers, and reactive silanes
  • Adhesives
  • Sealants
  • Lubricants
  • Electrical and thermal insulators and coatings
  • Non-stick, heat-resistant silicone cooking utensils and homeware
  • Automobile parts such as gaskets
  • Seals in aeroplanes
  • Keyboard pads in office machines
  • Tooth impression moulds and other silicone medical and dental apparatus
  • Coatings in waterproof paper and textiles
  • Also, grease, resin, oil, rubber, and caulk

Advantages of Silicones in Personal Care Products

Silicones offer several benefits in personal care products, making them a preferred ingredient in various formulations. Beyond reducing the white residue and sticky feel often associated with antiperspirants and deodorants, they also improve the texture and spreadability of many skincare and cosmetic products.

Silicones contribute to the “long-lasting” effect of cosmetics, helping to preserve colour vibrancy and enhance the shine of hair care products like shampoos and conditioners.

They are particularly beneficial in products with SPF, where their water-resistant properties help maintain effectiveness. Their lubricating and smoothing qualities ensure that lotions, sunscreens, and cleansers glide effortlessly onto the skin, creating a more uniform and comfortable application.

Solar Panel Efficiency with Silicone

Silicones are highly suitable for use in solar panels and photovoltaic components due to their resilience in withstanding prolonged exposure to sunlight and harsh environmental conditions.

While silicone is not used as a conductive material like silicon, it can be also used as a sealant and adhesive, providing essential protection against moisture, dust, and temperature fluctuations.

This enhances the efficiency, durability, and overall performance of solar panels and related devices. By reducing the risk of damage, wear, and tear, silicone materials help lower maintenance and replacement costs, contributing to the long-term reliability of solar energy systems.

Silicones in Electronics Manufacturing

Silicones are essential in the production of keypads, keyboards, copier rollers, and numerous components within computers, mobile electronics, and home entertainment systems. Their flexibility, durability, and resistance to wear make them a suitable for these high-usage parts.

Furthermore, silicones are used in LED lighting technology, where their excellent dielectric (insulating) properties and high thermal stability are critical. These characteristics make silicones ideal for a wide range of electrical and electronic applications, particularly in environments where heat resistance and insulation are required, though they are not used as conductive materials.

Enhancing Food Quality and Culinary Experience

Silicone-based cookware and bakeware provide several advantages, including a non-stick, non-toxic, and flexible surface that ensures food doesn’t absorb any taste or odour from the material. This makes them particularly easy to clean and maintain, enhancing their practicality in the kitchen.

In addition to these benefits, silicone products are highly durable and versatile. They are shatterproof and child-safe, making them ideal for family use. Their ability to withstand extreme temperatures means they are safe for use in the freezer, oven, microwave, and dishwasher, offering convenience and reliability in various cooking and storage scenarios

In Clothing and Sports Equipment

Silicone components allow manufacturers to create secure, watertight seals in goggles, diving masks, and other underwater equipment, ensuring long-lasting performance in challenging environments.

Beyond water sports, silicone has increasingly replaced rubber in various types of sports equipment due to its enhanced durability and flexibility.

The distinctive properties of silicone also allow for the development of innovative sportswear designs that are not only lightweight and durable but also provide excellent water repellence. At the same time, silicone ensures that the fabric remains breathable, making it ideal for high-performance athletic gear that requires both comfort and functionality.

Conclusion

In conclusion, while the terms silicon, silica, and silicone are often mistakenly used interchangeably, they refer to distinctly different materials with unique properties and uses. To recap:

  • Silicon is a metalloid chemical element widely used in electronics and as a semiconductor.
  • Silica is a naturally derived compound resulting from the interaction of oxygen and silicon, commonly found in nature and used in various industrial and consumer applications, including glass production and as a filler in paints, plastics, and rubber.
  • Silicone, on the other hand, is a synthetic, oily, rubber-like polymer made from siloxane or silicon oil. It has various applications in multiple industries, from personal care and home products to aerospace and electronics.

Understanding the differences between these materials is essential in order to select the appropriate material for your application and avoid any health hazards associated with its use.

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