Silicon
Silicon is a hard, brittle metalloid and the second most abundant element in Earth's crust, found almost everywhere as silica in sand, quartz, and countless other rock-forming minerals. Purified down to near-perfect crystals, it's also the foundation material of virtually every modern computer chip.
- Group · Period
- 14 · 3
- At room temp
- solid
- Melts at
- 1687 K
- Density
- 2.3296 g/cm³
- Discovered
- 1854
Uses
Silicon’s defining modern use is in electronics: ultra-pure silicon crystals are sliced into wafers and used to fabricate the transistors and integrated circuits found in essentially every computer, smartphone, and electronic device. Its semiconducting properties, refined and controlled through decades of manufacturing advances, make it the material at the core of the digital age. Silicon is also the key material in most photovoltaic solar panels, converting sunlight directly into electricity.
Beyond electronics, silicon compounds are everywhere in construction and industry: silica is a primary ingredient in glass and cement, and silicon is alloyed with metals like aluminum and steel to improve their strength and casting properties. Silicone polymers, made using silicon as a building block, are used in sealants, lubricants, and flexible, heat-resistant consumer products.
History
French chemist Henri Sainte-Claire Deville first prepared silicon in a crystalline form in 1854, three decades after Swedish chemist Jöns Jacob Berzelius had produced an impure, amorphous form of the element in 1824. Its name comes from the Latin word “silex,” meaning flint, a nod to how commonly the element occurs in ordinary rock and sand in the form of silica.
Fun facts
- Silicon is the second most abundant element in Earth's crust after oxygen, mostly locked up as silica in sand, quartz, and everyday rock.
- Ultra-pure silicon crystals form the base material for nearly all modern computer chips and most solar panels.
- Unlike carbon, silicon rarely bonds into long chains with itself — its chemistry is dominated instead by strong bonds to oxygen, which is why silicate minerals are so common.
Frequently asked questions
Why is silicon so important for computer chips?
Silicon is a semiconductor, meaning its ability to conduct electricity sits between a metal and an insulator and can be finely controlled by adding tiny amounts of other elements, a process called doping. That tunability, combined with silicon's abundance and well-understood processing, is why it became the backbone of the electronics industry.
Is silicon the same thing as silicone?
No, despite the similar name. Silicon is the chemical element itself. Silicone is a synthetic polymer built from silicon, oxygen, carbon, and hydrogen, used in products like sealants, cookware, and medical implants. Silicone is made using silicon as a raw ingredient, but the two have very different structures and properties.
Why can't ordinary sand be used directly in electronics?
Sand is mostly silica, a silicon-oxygen compound, but it also contains many impurities. Turning it into usable electronics-grade silicon requires extracting the silicon, then refining and purifying it to an extraordinarily high level, followed by growing it into large, flawless single crystals — a world away from raw sand.
Compounds
6 notable compounds containing Si
- Be3Al2Si6O18mineral
Beryl
A ring-silicate mineral whose color comes from trace impurities: chromium or vanadium produces emerald, while iron produces aquamarine.
Used for: Gemstone (emerald, aquamarine), primary ore of beryllium
- Lu2SiO5industrial
Lutetium oxyorthosilicate
A dense synthetic crystal, usually grown with a small amount of cerium doping, that converts incoming gamma rays into flashes of visible light extremely quickly.
Used for: Scintillator crystal in PET scanner detectors
- SiCindustrial
Silicon carbide
An extremely hard covalent network solid with a diamond-like lattice, rare in nature but produced in bulk synthetically.
Used for: Abrasives and cutting tools, semiconductor substrates, brake discs
- SiO2mineral
Silicon dioxide
A covalent network solid built from linked SiO4 tetrahedra, forming quartz crystals when ordered or ordinary glass when disordered.
Used for: Glassmaking, construction sand, silicon chip manufacturing
- Na2SiO3industrial
Sodium silicate
A soluble silicate salt made by fusing sand with sodium carbonate, sold as a thick, syrupy solution commonly called water glass.
Used for: Adhesives, detergent builder, egg preservation
- ZrSiO4mineral
Zirconium silicate (zircon)
A hard, durable mineral that is the main natural ore of zirconium and one of the oldest minerals found on Earth, prized for its brilliance when cut as a gemstone.
Used for: Gemstone, ceramic glaze opacifier, and primary ore of zirconium
Isotopes
23 known isotopes
Swipe to see all columns →
| Isotope | Natural abundance | Half-life | Decay mode | Mass excess | Binding energy / nucleon | Decay width |
|---|---|---|---|---|---|---|
| Si-28 stable | 92.2545% | Stable | — | -21,492.8 keV | 8,447.74 keV | — |
| Si-29 stable | 4.672% | Stable | — | -21,895.08 keV | 8,448.64 keV | — |
| Si-30 stable | 3.0735% | Stable | — | -24,432.96 keV | 8,520.65 keV | — |
Show all 23 isotopes
| Si-22 | — | 29 ms | Electron capture / beta-plus decay (100%), Beta-plus, proton emission (32%) | 33,640 keV | 6,044 keV | 1.57 × 10-14 eV |
| Si-23 | — | 42.3 ms | Electron capture / beta-plus decay (100%), ECP (88%), EC2P (3.6%) | 23,950 keV | 6,554 keV | 1.08 × 10-14 eV |
| Si-24 | — | 141.3 ms | Electron capture / beta-plus decay (100%), ECP (32.4%) | 10,745.19 keV | 7,167.23 keV | 3.23 × 10-15 eV |
| Si-25 | — | 220 ms | Electron capture / beta-plus decay (100%), Beta-plus, proton emission (35%) | 3,827.32 keV | 7,480.11 keV | 2.07 × 10-15 eV |
| Si-26 | — | 2.2453 s | Electron capture / beta-plus decay (100%) | -7,141 keV | 7,924.71 keV | 2.03 × 10-16 eV |
| Si-27 | — | 4.15 s | Electron capture / beta-plus decay (100%) | -12,384.51 keV | 8,124.34 keV | 1.10 × 10-16 eV |
| Si-31 | — | 157.24 m | Beta-minus decay (100%) | -22,949.04 keV | 8,458.29 keV | 4.84 × 10-20 eV |
| Si-32 | — | 157 Y | Beta-minus decay (100%) | -24,077.69 keV | 8,481.47 keV | 9.21 × 10-26 eV |
| Si-33 | — | 6.11 s | Beta-minus decay (100%) | -20,514.33 keV | 8,361.06 keV | 7.47 × 10-17 eV |
| Si-34 | — | 2.77 s | Beta-minus decay (100%) | -19,991.68 keV | 8,337.17 keV | 1.65 × 10-16 eV |
| Si-35 | — | 0.78 s | Beta-minus decay (100%), Beta-minus, neutron emission (5%) | -14,391.48 keV | 8,169.56 keV | 5.85 × 10-16 eV |
| Si-36 | — | 0.45 s | Beta-minus decay (100%), Beta-minus, neutron emission (10%) | -12,436.13 keV | 8,112.52 keV | 1.01 × 10-15 eV |
| Si-37 | — | 90 ms | Beta-minus decay (100%), Beta-minus, neutron emission (17%), B-2N | -6,571.51 keV | 7,952.9 keV | 5.07 × 10-15 eV |
| Si-38 | — | 63 ms | Beta-minus decay (100%), Beta-minus, neutron emission (25%) | -4,170.3 keV | 7,892.83 keV | 7.24 × 10-15 eV |
| Si-39 | — | 47.5 ms | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | 2,320.35 keV | 7,730.98 keV | 9.61 × 10-15 eV |
| Si-40 | — | 33.0 ms | Beta-minus decay (100%), B-2N, Beta-minus, neutron emission | 5,666.88 keV | 7,655.82 keV | 1.38 × 10-14 eV |
| Si-41 | — | 20.0 ms | Beta-minus decay (100%), Beta-minus, neutron emission (0%) | 13,200 keV | 7,482 keV | 2.28 × 10-14 eV |
| Si-42 | — | 12.5 ms | Beta-minus decay (100%), Beta-minus, neutron emission, B-2N | 16,840 keV | 7,410 keV | 3.65 × 10-14 eV |
| Si-43 | — | 60 ns | Beta-minus decay, Beta-minus, neutron emission, B-2N | 24,330 keV | 7,251 keV | 7.60 × 10-9 eV |
| Si-44 | — | 360 ns | Beta-minus decay (100%), Beta-minus, neutron emission | 29,310 keV | 7,156 keV | 1.27 × 10-9 eV |