Silicon, Si

Silicon is the chemical element that has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon. As the eighth most common element in the universe by mass, silicon occasionally occurs as the pure free element in nature, but is more widely distributed in dusts, planetoids and planets as various forms of silicon dioxide (silica) or silicates. On Earth, silicon is the second most abundant element (after oxygen) in the crust,[1] making up 25.7% of the crust by mass.

Silicon has many industrial uses. Elemental silicon is the principal component of most semiconductor devices, most importantly integrated circuits or microchips. Silicon is widely used in semiconductors because it remains a semiconductor at higher temperatures than the semiconductor germanium and because its native oxide is easily grown in a furnace and forms a better semiconductor/dielectric interface than any other material.

In the form of silica and silicates, silicon forms useful glasses, cements, and ceramics. It is also a constituent of silicones, a class-name for various synthetic plastic substances made of silicon, oxygen, carbon and hydrogen, often confused with silicon itself.

Silicon is an essential element in biology, although only tiny traces of it appear to be required by animals. It is much more important to the metabolism of plants, particularly many grasses, and silicic acid (a type of silica) forms the basis of the striking array of protective shells of the microscopic diatoms.

Technical Data
Symbol Si Density (20°C)/gcm3 2.336 (ß2.905
Atomic number 14 Melting point / °C 1420
No. of naturally occurring isotopes 3 Boiling point / °C -3280
Atomic weight 28.0855(+/-3) ΔHfus/kJmol-1 50.6
Electronic configuration [Ne]3s23p2 ΔHvap/kJmol-1 383
rIV(covalent)/pm 117.6 ΔHf(monoatomic gas)/kJmol-1 454
rIV (ionic, 6-coordinate)/pm 40 Ionization energy)/kJmol-1 I 786.3
Electrical resistivity (20°C)/μohm cm ~48 Ionization energy)/kJmol-1 II 1576.5
Pauling electronegativity 1.8 Ionization energy/kJmol-1 III 3228.3
Band gap Eg/kJmol-1 106.8 Ionization energy/kJmol-1 IV  
Evaporation Techniques
Temperature (oC) @Vap. Pressure Techniques Remarks
10-8 Torr 10-6 Torr 10-4 Torr Electron Beam Crucible Coil Boat
992 1147 1337 Fair Tantalum & Vitreous Graphite - Tungsten & Tantalum Alloys with Tungsten; use heavy Tungsten Boat. SiO produced above 4x 10-6 Torr. EB Best

Evaporation Materials
S4-5001-M pieces 3-6mm
S4-5002-M pieces 25mm and smaller
S4-10003-P -325 mesh