What is the difference between Silicon, Silica, and Silicone?
Most people confuse Silicon, Silica, and Silicone with being the same, but all three are quite different. Here is a brief description of each for a better understanding of Silicon vs Silica vs Silicone.
Silicon is one of the 97 building blocks that form our minerals. It is a chemical element represented by the symbol “Si,” and its atomic number is 14. It is a hard semiconductor and tetravalent metalloid, which is a brittle crystalline solid element with a bluish-grey metallic lustre.
It is also the second most abundant chemical element found in the earth’s crust. Do you know silicon makes about 27% of an average rock? Silicon also links up and interacts with oxygen from an essential suite of earth’s minerals known as silicates. These include olivine, Quartz, micas, jadeite, feldspars, thomsonite, and prehnite. Due to the abundance of oxygen in the earth’s crust, it is rare to find pure native silicon in its natural form.
Characteristics of Silicon
Silicon has boiling and melting points at 3265 ⁰C and 1414 ⁰C respectively. There are fourteen electrons in a silicon atom. Their electronic configuration is a ground state that is [Ne] 3s23p2. Four out of these are valence electrons occupying two 3p orbitals and one of the 3s orbital.
Mostly, silicon uses are for a commercial purpose that does not require separation and required minimum processing of any silicon-based natural minerals. Some of the silicon uses include its industrial application in constructions with silica sand, clays, and stone.
Portland cement uses silicates for stucco and mortar. Mix it with gravel and silica sand, and you have got concrete for walkways, roads, and foundations. Silicon is also useful in producing white-ware ceramics like porcelain.
Silicon carbides, which are silicon compounds, can be helpful as abrasives and material for high-strength ceramics. Silicon also provides the basis for synthetic polymers known as silicones, which we will discuss later in this article.
From the late 20th to early 21st century has been coined as Silicon Age, also known as “Information Age” or “Digital Age.” It is all due to the significant impact of elemental silicon on the economy of the modern world.
Although used in a small portion in semiconductor electronics at less than 10%, the highly purified silicon element is essential to MOS or metal-oxide silicon transistors. Integrated chips also use silicon in the most advanced technology, such as cell phones and computers.
For example, Metal-oxide Silicon Field-Effect Transistors or MOSFET is the most popular and successful silicon device. It is probably the most manufactured device in a large number than any other in the history of technology and sciences. Industries such as aluminium-casting, steel refining, and fine chemical producers often use free silicon to make fumed silica.
Silicon is also one of the essential elements 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.
Silica, or also known as Silicon dioxide, is as the name suggests an oxide of silicon. It has a chemical formula SiO₂ and mostly found naturally in the form of Quartz as well as in diverse species of living organisms. You will discover silica as one of the significant constituents of sand in many parts across the world.
It is one of the most abundant and most complex families of materials. It only exists as synthetic products and compounds of various minerals. Some of the notable examples include fumed silica, aerogels, fused Quartz, and silica gel.
How is silica gel made?
Silica gel manufactured for many years are commonly used as desiccants to absorb moisture to protect goods in their packaging. The process involves a combination of acid and water glass solution. Timing is vital in the process as the formation of the gels are immediate during the composition. Upon completion, the silica gel will be distributed accordingly by its mesh size using layers of mesh screens from the top. The silica gel has to go through a washing process with ammonia to remove any excess salt and then dried using oven drying.
Find our more about silica gel bags in our video here.
Silica has uses in structural materials and as electrical insulators in microelectronics. You will also find silica as a compound in the pharmaceutical and food industries.
You must also know that inhaling crystalline silica is toxic to humans. Do take note that silica gel which is amorphous silica is not crystalline silica. It can harm your 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.
In most silicates, a silicon atom displays tetrahedral coordination, which means four oxygen atoms surround a single silicon atom in the centre. Quartz polymorphs are the most common example of this phenomenon. It is a 3D network solid that has each silicon atom bond covalently in a tetrahedral fashion to four oxygen atoms.
However, molten silica is known for exhibiting various peculiar physical behaviour and characteristic, similar to those in liquid water. These include density maximum at 5000⁰ C temperatures, negative temperature expansion, and heat capacity minimum. Molten silica’s density slides from 2.08 g/cm3 at temperatures 1950⁰C to 2.03 g/cm3 at increased temperatures of 2200 ⁰C.
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.
In the industry, silicones are a significant element used in adhesives, sealants, lubricants, cooking utensils, medicine, and electrical and thermal insulations. Some of the common forms of silicone include silicone grease, silicone resin, silicone oil, silicone rubber, and silicone caulk.
The more precise term to define silicone is polymerized siloxanes. It has a backbone chain consisting of inorganic silicon-oxygen atom bond represented as (⋯–Si–O–Si–O–Si–O–⋯) where each silicon centre has two organic groups attached to it.
These organic groups are commonly methyl. The materials can either be polymeric or cyclic. By varying the backbone chain length, crosslinking, and side groups, you can synthesize silicone with various compositions and properties.
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 of siloxane.
Do you know 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 aeroplanes
- Keyboard pads in office machines
- Tooth impression moulds and other medicine and dentistry industries
- Coatings in paper and textiles