Silicon
Simplified 2D Bohr model:Central red circle is the nucleus (proton). Blue ring represents the electron's orbit. Small blue dot is the electron. Note: This basic model doesn't show quantum behavior.
CLASSIFICATION:
Metalloid
Silicon exhibits properties of both metals and nonmetals, placing it in the metalloid category. This duality contributes to its diverse chemical behavior and technological applications.
28.0855 u
Appearance: Blue-grey crystalline solid with a metallic luster
Silicon, a cornerstone of the modern world, is a metalloid renowned for its semiconducting properties. As the second most abundant element in the Earth's crust (27.7% by weight), it plays a crucial role in various industries, from electronics and solar energy to construction and materials science. Its unique blend of metallic and non-metallic characteristics makes it a versatile element with a wide range of applications.
14
14
14 (most common isotope)
eV
4. Discovery and History
1414 °C
3265 °C
2.33 g/cm³ at 20 °C
111 pm
12.1 cm³/mol
111 pm
19.789 J/(mol·K)
149 W/(m·K)
8433 m/s at 20 °C
2.33 g/cm³ at 20 °C
6.5
149 W/(m·K)
Not applicable due to its brittleness
0.705 J/(g·K) at 25 °C
2.6 µm/(m·K) at 25 °C
Transitions from solid to liquid at 1414 °C and boils at 3265 °C under standard atmospheric pressure.
Silicon forms a protective oxide layer (SiO2) upon exposure to air, rendering it relatively inert. However, it reacts with halogens, dilute alkalis, and at high temperatures with other elements.
+4, -4
Not applicable as silicon does not readily form ions in solution.
Silicon predominantly exists in the +4 oxidation state, forming stable compounds like silicon dioxide and silicates. Its ability to share electrons through covalent bonding underpins its role in various materials and compounds.
Diamagnetic
2.3×10³ Ω·m at 20 °C for intrinsic silicon
Negative, indicating that the majority charge carriers in intrinsic silicon are electrons
~3.4 for intrinsic silicon
High reflectivity in polished form, making it useful in mirrors and optical components
Silicon absorbs strongly in the infrared region, which is crucial for its application in solar cells and infrared detectors.
n = 3 for silicon's valence electrons (l = 0 for s orbital and l = 1 for p orbitals)
Total Electrons: 14, Shells: 1s², 2s² 2p⁶, 3s² 3p²
-8.1517 eV for the ionization energy
[Ne] 3s² 3p²
This electron configuration indicates that silicon has four valence electrons in its outermost energy level (3s² 3p²), allowing it to form four covalent bonds with other atoms.
Terrestrial Abundance
Silicon is widely distributed in the Earth's crust, primarily as silicon dioxide (silica) in the form of sand, quartz, and various silicate minerals.
Diamond Cubic
Temperature: Room temperature and pressure
Silicon adopts a diamond cubic crystal structure, similar to diamond, with each silicon atom covalently bonded to four neighboring silicon atoms. This arrangement contributes to its semiconducting properties.
+4, -4
The most common oxidation state, found in silicon dioxide, silicates, and most silicon compounds., A less common oxidation state, observed in silanes and some silicon-metal compounds.
Silicon Dioxide (SiO2)
SiO2
Commonly known as silica or quartz, it is the most abundant silicon compound, forming the basis of sand, glass, and many minerals. Its diverse crystalline forms exhibit various properties, making it useful in optics, electronics, and construction.
Silicon Carbide (SiC)
SiC
An exceptionally hard and chemically inert compound with high thermal conductivity, used in abrasives, high-temperature ceramics, and electronic devices.
Silanes (SiH4, Si2H6, etc.)
SiₙH₂ₙ₊₂
A group of silicon-hydrogen compounds analogous to alkanes, often used in the production of semiconductors and as precursors to silicon-based materials.
Silicones (Polysiloxanes)
[R2SiO]ₙ
A versatile family of polymers with a silicon-oxygen backbone, known for their heat resistance, flexibility, and water repellency. Silicones find applications in sealants, adhesives, lubricants, and medical implants.
Silicates
Variable
A vast group of minerals containing silicon, oxygen, and various metals, forming the Earth's crust. Examples include feldspar, mica, and clay minerals.
Several lines in the ultraviolet and visible spectrum nm
Variable
Emission and absorption lines, depending on the excitation conditions
A non-crystalline form of silicon with disordered atomic arrangement, often used in thin-film solar cells and displays.
17. Practical Applications
Semiconductor Devices
Silicon's semiconducting properties make it the foundation of transistors, integrated circuits, and microchips, driving the modern electronics industry.
Solar Energy
Silicon is the primary material in photovoltaic cells used in solar panels, converting sunlight into electricity and playing a key role in renewable energy.
Construction Materials
Silicon dioxide, in the form of sand and quartz, is a key ingredient in glass, concrete, and ceramics, contributing to the structural integrity and durability of buildings and infrastructure.
Silicones and Polymers
Silicones are used in a wide range of applications, including sealants, adhesives, lubricants, medical implants, and cookware due to their unique properties.
Alloys and Composites
Silicon is added to metals to improve their strength, castability, and corrosion resistance, forming alloys used in automotive and aerospace industries.
26. Synthesis and Production
Silicon is primarily produced through carbothermic reduction of silica (SiO2) using carbon in an electric arc furnace.
The extraction process involves the reduction of quartz sand with coke at high temperatures.
Silicon production is a significant global industry, with China being the largest producer, followed by Russia and Norway.
20. Economic Data
Market Price: Variable, depending on purity and form
Producing Countries: Major producers include China, Russia, Norway, and the United States, with production focused on both metallurgical-grade and high-purity semiconductor-grade silicon.
Industrial Use: N/A
Description: N/A
18. Biological Role
Trace Element
While not considered essential for humans, silicon plays a structural role in some organisms, such as diatoms and sponges. It is also beneficial for bone health and collagen formation in animals.
Regulations focus on occupational exposure limits for crystalline silica dust to prevent silicosis and other respiratory diseases.
Environmental regulations govern the disposal and recycling of silicon-containing waste and electronic devices.
19. Health and Environmental Impact
Inhalation of crystalline silica dust can lead to silicosis and other respiratory problems. However, silicon in its elemental or bound forms is generally non-toxic.
Mining and processing of silicon-containing materials can have environmental impacts, including habitat destruction and water pollution. However, silicon-based technologies like solar panels contribute to sustainable energy solutions.
27. Environmental Safety
Inhalation of fine crystalline silica dust can cause silicosis, a serious lung disease. However, silicon in its elemental or bound forms is generally considered non-toxic.
Proper ventilation and protective equipment are essential when handling silica dust. Silicon wafers and most silicon compounds pose minimal health risks.
Handling: N/A
Storage: N/A
First Aid Measures: N/A
23. Future Predictions
Advancements in Silicon Technology
Continued research and development in silicon-based technologies are expected, leading to more efficient solar cells, faster and more powerful electronics, and novel materials with enhanced properties.
Silicon in Emerging Fields
Silicon-based materials are likely to play a role in emerging fields such as nanotechnology, biotechnology, and energy storage, contributing to advancements in various sectors.