| Astrophysics (Index) | About |
Silicon (Si) is the element with atomic number 14, symbol Si. Its most common isotope has mass number 28, but 29 and 30 are also stable. It is abundant on the Earth's surface and crust, a major component of rock, sand, and glass, in silicate form since it is highly reactive. Its nuclei are synthesized by oxygen burning and the alpha process, in large stars and in supernovae. Silicon spectral lines are sometimes used in metallicity studies. Silicon burning is essentially the alpha process starting at silicon, which in some early stars produces the heaviest common elements, nickel and iron.