Si · Element 14 · Metalloid
The element that turned sand into civilisation's substrate: every processor you have ever used is a slab of ultrapure silicon.
Structure
Not a diagram of dots on rings — a Monte-Carlo sample of the actual probability density |ψ|² for each occupied subshell. Drag to rotate. Blue and violet mark opposite signs of the wavefunction, which is what makes bonding possible.
Measured values
Every bar shows where silicon sits among all 118 elements for that property.
Sources: IUPAC 2021 standard atomic weights · CRC Handbook of Chemistry and Physics · NIST. Values marked ~ are predicted rather than measured.
Same element, different neutrons
All silicon atoms have the same number of protons, 14, and differ only in their number of neutrons: those variants are its isotopes. The most common, Si-28, has 14 neutrons and makes up 92.2545% of natural silicon.
| ISOTOPE | Neutrons | Natural Abundance | Half-life | Decay Mode |
|---|---|---|---|---|
| Si-28 most common | 14 | 92.2545% | Stable | — |
| Si-29 | 15 | 4.672% | Stable | — |
| Si-30 | 16 | 3.0735% | Stable | — |
Here the classroom shortcut, rounded atomic mass (28.085) minus atomic number, gives the same answer: 14.
Data: IAEA Nuclear Data Section, LiveChart of Nuclides, ground-state evaluations, retrieved October 10, 2026. Abundance is the share of atoms in the natural element; a dash means the isotope has no standard natural abundance.
Size, to scale
Radius 111 pm — that is 0.111 nm, so about 4.5 million of them side by side would span a millimetre.
Thermal range
Silicon is liquid over a 1851 K window, from 1687 K to 3538 K.
The story
Silicon is the element that built the Information Age and makes up most of the ground beneath your feet. After oxygen, it's the most abundant element in Earth's crust, forming the backbone of rocks, sand, and glass. But silicon's real change came when scientists learned to purify it to 99.9999999% - creating the semiconductor chips that power every computer, smartphone, and digital device. Silicon Valley got its name from this element that can switch between conducting and insulating electricity billions of times per second. From ancient glass windows to modern solar panels, from computer chips to breast implants, silicon shapes our world in countless ways. Every grain of sand on every beach is mostly silicon dioxide, making castles from the same element that runs your smartphone.
Silicon's discovery story spans millennia, from ancient glassmakers who unknowingly used silicon compounds to 19th-century chemists who isolated the pure element, ultimately enabling the digital age that defines modern civilization.
Humans have utilized silicon compounds for over 9,000 years without knowing it. Archaeological evidence shows that ancient civilizations mastered silicate technology long before understanding atomic theory.
7000 BCE: First pottery using silicon-rich clays in China and Middle East
3500 BCE: Mesopotamian glassmaking using silica sand and potash
1500 BCE: Egyptian artisans created intricate glass vessels using silicon dioxide
500 BCE: Roman concrete incorporated volcanic ash (pozzolan) rich in amorphous silica
The Romans unknowingly created some of the most durable concrete in history using silicon-rich volcanic ash from Mount Vesuvius. The Pantheon in Rome, built in 126 CE, still stands today partly due to its silicon-enhanced concrete dome.
The scientific investigation of silicon began during the Age of Enlightenment when chemists started systematically studying minerals and compounds.
French chemist Antoine-Laurent de Lavoisier first suspected that silica (SiO₂) contained an unknown element. In his important 1789 work "Elementary Treatise on Chemistry," Lavoisier listed silica among compounds he believed contained undiscovered elements, laying groundwork for future isolation attempts.
Multiple chemists across Europe competed to isolate pure silicon, leading to conflicting claims and scientific controversy that lasted over a decade.
British chemist Sir Humphry Davy (1778-1829) first attempted silicon isolation in 1808 using his newly invented electric battery. Davy tried electrolyzing silica but only succeeded in producing an impure, dark powder. Though unsuccessful, he proposed the name "silicium"; Thomas Thomson changed it to "silicon" in 1817 from Latin "silex" (flint) plus the suffix "-on" (like carbon and boron).
French chemists Gay-Lussac (1778-1850) and Thénard (1777-1857) attempted silicon isolation by heating potassium with silicon tetrafluoride (SiF₄). They produced a brown powder they believed was silicon, but later analysis revealed it contained significant silicon compounds rather than pure element.
Swedish chemist Jöns Jacob Berzelius (1779-1848) achieved the first confirmed isolation of pure silicon on May 15, 1824. His systematic approach and meticulous documentation established him as silicon's true discoverer.
Berzelius heated silicon tetrafluoride (SiF₄) with metallic potassium in an iron crucible:
SiF₄ + 4K → Si + 4KF
His innovation was washing the product with water to remove potassium fluoride, then with dilute hydrochloric acid to dissolve any unreacted potassium, leaving behind pure silicon. His product was a brown powder of amorphous silicon.
Silicon remained a laboratory curiosity until industrial applications emerged in the late 19th century.
French chemist Henri Sainte-Claire Deville (1818-1881) improved silicon production by reducing silica with aluminum powder at high temperatures. This method produced silicon on a larger scale, enabling the first commercial applications.
Edward Goodrich Acheson (1856-1931) developed the electric furnace process for producing silicon carbide (carborundum) and later pure silicon. His company, The Carborundum Company, became the first major silicon producer, supplying abrasives and later semiconductor materials.
Silicon's transformation from laboratory novelty to civilization-defining material began during World War II with the development of radar technology.
1940: Russell Ohl at Bell Labs discovered the photovoltaic effect in silicon
1947: First transistor invented (germanium-based) by Bardeen, Brattain, and Shockley
1954: Bell Labs created the first practical silicon solar cell (6% efficiency)
1958: Jack Kilby invented the integrated circuit using germanium; Robert Noyce improved it with silicon
1961: First commercial silicon integrated circuits began production
1971: Intel introduced the 4004 microprocessor - the first computer on a chip
Today, silicon enables global communication, artificial intelligence, renewable energy, and space exploration. From Berzelius's tiny brown powder in 1824 to powering billion-transistor processors, silicon's journey represents one of chemistry's most transformative discoveries.
Berzelius's Legacy: The Swedish chemist who isolated silicon could never have imagined that his brown metallic powder would become the foundation of modern electronics. Every smartphone, computer, and solar panel traces its lineage back to that fateful day in 1824 when Berzelius first held pure silicon in his hands.
Applications
Silicon's unique semiconductor properties have transformed human civilization, enabling the digital age and modern technology. From smartphones to spacecraft, silicon-based devices power our interconnected world.
Silicon dominates semiconductor manufacturing, comprising over 95% of all computer chips. The element's crystalline structure and controllable electrical properties make it ideal for creating transistors, diodes, and integrated circuits.
Silicon Wafers: Ultra-pure silicon ingots (99.9999999% pure) are sliced into wafers 200-300mm in diameter and 0.775mm thick. Leading-edge processors use 3nm process technology, fitting up to about 92 billion transistors on a single chip (Apple's M3 Max).
Doping Process: Pure silicon is "doped" with trace amounts of phosphorus (n-type) or boron (p-type) to create semiconductive properties. This process involves ion implantation at energies of 1-200 keV, precisely controlling electrical conductivity.
Photolithography: Silicon wafers undergo photolithography using extreme ultraviolet (EUV) light at 13.5nm wavelength. ASML's EUV machines, costing $200 million each, enable the precise patterning required for modern processors.
Silicon photovoltaic cells convert sunlight directly into electricity through the photovoltaic effect. Modern silicon solar panels achieve 22-26% efficiency in commercial applications.
Silicon compounds form the backbone of modern construction through glass, concrete, and ceramics. Silicates constitute 90% of Earth's crust and are essential building materials.
Modern vehicles contain over 1,000 silicon-based semiconductors controlling engines, safety systems, and infotainment. Electric vehicles use silicon carbide (SiC) power electronics for improved efficiency.
SiC MOSFETs: Tesla Model 3 uses silicon carbide inverters operating at 650V, improving power efficiency by 5% and reducing charging time. SiC switches at 10 kHz vs. 2 kHz for silicon, enabling smaller, lighter components.
Sensor Applications: Silicon MEMS (Micro-Electro-Mechanical Systems) create accelerometers, gyroscopes, and pressure sensors for airbag deployment, stability control, and tire pressure monitoring.
Silicon technology enables GPS navigation, satellite communication, and space exploration. Radiation-hardened silicon chips survive the harsh environment of space.
Silicon biocompatibility enables medical implants, diagnostic equipment, and drug delivery systems. Silicon's inert properties make it ideal for long-term implantation.
Silicon technology surrounds us in countless forms, often invisible but always essential. From morning alarms to bedtime entertainment, silicon makes modern life possible.
Transistors in a single iPhone 13 processor
Connected devices worldwide by 2025
Purity level required for semiconductor silicon
Global semiconductor sales (2025)
The average smartphone contains more computing power than the computers that guided Apollo 11 to the moon. That same phone has over 1 billion transistors - if each transistor were a person, they could populate China with room to spare.
Where it comes from
282000 mg/kg of Earth's crust · more abundant than 99% of elements
Silicon is the second most abundant element in Earth's crust at 28.2% by weight, exceeded only by oxygen. This abundance makes silicon the fundamental building block of our planet's geology and the foundation for all silicon-based technology.
Silicon never occurs in pure metallic form in nature due to its high reactivity with oxygen. Instead, it forms countless minerals and compounds that literally build our planet's structure.
The most common silicon mineral, comprising 12% of Earth's crust. Found in:
Notable Locations: Brazilian quartz mines, Arkansas crystal deposits, Herkimer "diamonds" (NY)
Most abundant mineral group in Earth's crust (50-60%), including:
Formation: High-temperature crystallization in igneous rocks
Weathering products of feldspar-rich rocks:
Economic Importance: Pottery, paper coating, drilling mud
Dark silicate minerals in mafic rocks:
Occurrence: Basalt, gabbro, volcanic rocks
Silicon's cosmic journey began in the cores of massive stars during oxygen burning and silicon burning processes. When stars at least 8 times the mass of our Sun reach the end of their lives, they create silicon through nuclear fusion.
Oxygen Burning (1.5-2 billion K): ¹⁶O + ¹⁶O → ²⁸Si + ⁴He
Silicon Burning (3+ billion K): ²⁸Si + ⁴He → ³²S + γ
During a supernova explosion, these silicon-rich stellar cores are dispersed throughout the galaxy, eventually becoming part of new star systems like our own. The silicon in your smartphone was literally forged in the heart of a dying star billions of years ago.
Silicon played a crucial role in planetary formation through:
4.6 billion years ago: Solar nebula condensation formed silicon-rich dust grains
4.5 billion years ago: Accretion of silicate planetesimals
4.4 billion years ago: Earth's core-mantle differentiation concentrated silicon in the mantle
4.0 billion years ago: Crystallization of first continental crust (silicon-rich granite)
3.8 billion years ago: Formation of stable cratons with silicon-aluminum framework
Silicon occurs naturally in water as dissolved silicic acid (H₄SiO₄), typically at concentrations of 1-30 mg/L. Ocean water contains approximately 3 mg/L dissolved silicon, essential for diatom growth.
Silicon Valley Connection: The famous technology hub got its name from the silicon semiconductors developed there, though ironically, most silicon now comes from Asia, not California.
Handling
Silicon in its pure form and many compounds presents minimal health risks under normal conditions. However, certain silicon compounds and industrial processes require careful safety considerations, particularly crystalline silica exposure.
OSHA PEL: 0.05 mg/m³ (respirable crystalline silica, 8-hour TWA)
Primary Risk: Silicosis - progressive, incurable lung disease from inhaling crystalline silica dust
High-Risk Activities: Sandblasting, mining, quarrying, concrete cutting, pottery making
Symptoms: Shortness of breath, persistent cough, fatigue, chest pain, respiratory failure (advanced cases)
Progression: Simple silicosis (15-20 years) → Progressive massive fibrosis → Death
IARC Classification: Group 1 carcinogen (crystalline silica from occupational sources)
Related Diseases: Lung cancer, COPD, kidney disease and autoimmune disorders
Risk Factors: Duration and intensity of exposure, particle size, surface reactivity
Prevention: Engineering controls, respiratory protection, medical surveillance
Eye Contact: Silicon dust can cause mechanical irritation and corneal abrasion
Skin Contact: Generally non-irritating, but abrasive dusts may cause cuts or mechanical irritation
Ingestion: Large amounts may cause gastrointestinal irritation but not systemic toxicity
Silicon Wafer Handling: Sharp edges can cause lacerations; use proper handling tools and cut-resistant gloves
Chemical Exposure: Silicon processing involves hydrofluoric acid, requiring specialized safety protocols
High-Temperature Operations: Silicon melting (1414°C) requires thermal protection and emergency procedures
Action: Flush immediately with clean water for 15 minutes. Remove contact lenses if easily removable. Do not rub eyes.
Medical Attention: Seek immediate medical care if irritation persists or if particles embedded in eye.
Immediate Action: Move person to fresh air immediately. Remove from dust exposure source.
Medical Response: If breathing difficulties occur, administer oxygen and transport to medical facility.
Documentation: Record exposure details for medical evaluation and workers' compensation.
Minor Exposure: Wash with soap and water. Remove contaminated clothing.
Lacerations: Control bleeding, clean wound, apply sterile dressing. Sharp silicon fragments may require medical removal.
Action: Rinse mouth with water. Do not induce vomiting unless directed by medical personnel.
Large Amounts: Seek medical attention if significant quantities consumed or symptoms develop.
• Silicon in consumer electronics (phones, computers) poses no health risks during normal use
• Silicone cookware and other food-grade silicone products are safe for food contact
• Solar panels contain encapsulated silicon that does not present exposure risks
• Glass products (silicon dioxide) are safe for everyday use
Quick answers
Silicon (symbol Si) is element 14 on the periodic table, a metalloid in period 3, group 14. The element that turned sand into civilisation's substrate: every processor you have ever used is a slab of ultrapure silicon. At room temperature it is a solid.
[Ne] 3s² 3p², giving 3 occupied shells with the distribution 2, 8, 4. Its outer shell holds 4 electrons, which is what sets its bonding behaviour.Silicon melts at 1687 K (1413.9 °C) and boils at 3538 K (3264.9 °C).
The standard atomic weight of silicon is 28.085 u. That is a weighted average across its naturally occurring isotopes, which is why it is rarely a whole number.
The most common silicon atom, Si-28, has 14 neutrons: its mass number, 28, minus its atomic number, 14. It makes up 92.2545% of natural silicon. The classroom shortcut, rounded atomic mass (28.085) minus atomic number, gives the same 14.
Silicon has a density of 2.33 g/cm³. Water is 1.0 g/cm³, so a block of silicon is about 2.3× heavier.
Silicon has a Pauling electronegativity of 1.9. The scale runs from 0.70 (francium, the least greedy for electrons) to 3.98 (fluorine, the most). Values in this middle band tend to form covalent rather than strongly ionic bonds.
Silicon was discovered in 1824 by Jons Jacob Berzelius. Origin of the name: Latin silex, "flint".
Silicon makes up about 28.2% of the Earth's crust — one of the most abundant elements there is.