Silicon (Si)
Stable isotopes of silicon available from ISOFLEX
| Isotope | Z(p) | N(n) | Atomic Mass | Natural Abundance | Enrichment Level | Chemical Form |
| Si-28 | 14 | 14 | 27.9769265 | 92.23% | 99.90-99.99% | Elemental |
| Si-28 | 14 | 14 | 27.9769265 | 92.23% | 99.90-99.99% | Oxide |
| Si-29 | 14 | 15 | 28.9764947 | 4.67% | >99.00% | Elemental |
| Si-29 | 14 | 15 | 28.9764947 | 4.67% | >99.00% | Oxide |
| Si-30 | 14 | 16 | 29.9737702 | 3.10% | >99.00% | Elemental |
| Si-30 | 14 | 16 | 29.9737702 | 3.10% | >99.00% | Oxide |
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The discovery of silicon is credited to Jöns Jakob Berzelius in 1824 in Sweden. Its name originates with the Latin word silicis, which means “flint.” It is the second most abundant element, exceeded only by oxygen, making up 25.7% of the earth's crust by weight.
Silicon exists in two allotropic modifications: Crystalline silicon is made up of grayish-black lustrous needle-like crystals, or octahedral platelets, with a cubic structure. Amorphous silicon is a brown powder. Elemental silicon is relatively stable in most substances at ordinary temperatures and shows similarity to other elements of its group. It exists as sand quartz, flint, amethyst, agate, opal, jasper and rock crystal.
Silicates and silica have many applications in numerous fields, including making cements and concretes for building materials, glasses and glassware, ceramics, pigments, adsorbents, paper boards, fillers, detergents, precious gems, catalysts and water-softeners. Silicones are used as lubricants and in making rubbers, plastics, electrical coatings, adhesives, paints and varnishes, and as water repellents for textiles, papers and concrete. Elemental silicon has a major application in computer chips. Silicon of hyperpurity — doped with trace elements, such as boron, phosphorus, arsenic or gallium — is one of the best semiconductors and is used in transistors, power rectifiers, diodes and solar cells. Hydrogenated amorphous silicon converts solar energy into electricity.
Inhalation of silica dusts or silicate mineral dusts can cause silicosis or other lung diseases.
Properties of Silicon
| Name | Silicon |
| Symbol | Si |
| Atomic number | 14 |
| Atomic weight | 28.08555 |
| Standard state | Solid at 298 °K |
| CAS Registry ID | 7440-21-3 |
| Group in periodic table | 14 |
| Group name | None |
| Period in periodic table | 3 |
| Block in periodic table | p-block |
| Color | Dark gray with a bluish tinge |
| Classification | Semi-metallic |
| Melting point | 1414 °C |
| Boiling point | 2355 °C |
| Thermal conductivity | 149 W/(m·K) at 298.2 °K |
| Electrical resistivity | 3-4 µΩ·cm at 0 °C |
| Electronegativity | 1.80 |
| Specific heat | 0.71 kJ/kg K |
| Heat of vaporization | 359 kJ·mol-1 |
| Heat of fusion | 50.2 kJ·mol-1 |
| Density of high-purity liquid | 2.53 g/cm3 at 1414 °C |
| Density of solid | 2.33 g/cm3 |
| Electron configuration | [Ne]3s23p2 |
| Atomic radius | 1.173 Å |
| Oxidation state | +4 |
| Critical temperature | 4 °C |
| Calculated crucial pressure | 530 atm |
Research
- Silicon isotopes as a new method of measuring silicate mineral reaction rates at ambient temperature
- Mass bias stabilization by Mg doping for Si stable isotope analysis by MC-ICP-MS
- Tuning thermal transport in Si nanowires by isotope engineering
- A proton density bubble in the doubly magic 34Si nucleus
- Experimental Determination of Silicon Isotope Fractionation in Rice
- A review of the stable isotope bio-geochemistry of the global silicon cycle and its associated trace elements
- Whole-Ocean Changes in Silica and Ge/Si Ratios During the Last Deglacial Deduced From Long‐Lived Giant Glass Sponges