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Silicon, including Technical Data, Safety Data and its high purity propertiesresearch, applications and other useful facts are discussed below. Scientific facts such as the atomic structure,ionization energyabundance on Earthconductivity and thermal properties are included. 

Silicon is one of man‘s most useful elements. It makes up 25.7% of the earth‘s crust, by weight, and is the second most abundant element, being exceeded only by oxygen. The Czochralski process is commonly used to produce single crystals of silicon used for solid-state or semiconductor devices. Silica, as sand, is a principal ingredient of glass, one of the most inexpensive of materials with excellent mechanical, optical, thermal, and electrical properties. Silicon is available as metal and compounds with purities from 99% to 99.9999% (ACS grade to ultra-high purity); metals in the form offoil, sputtering target, and rod, and compounds as submicron and nanopowderUltra high purity silicon can be doped with borongallium, phosphorus , or arsenic to produce silicon for use in transistors,solar cells, rectifiers, and other solid-state devices which are used extensively in the electronics and space-age industries. Hydrogenated amorphous silicon has shown promise in producing economical cells for converting solar energy into electricity. Silcones are important products of silicon. They range from liquids to hard, glasslike solids with many useful properties. Thin film deposition of Silicon Nanoparticlequantum dots on the polycrystalline silicon substrate of a photovoltaic (solar) cell increases voltage output as much as 60% by fluorescing the incoming light prior to capture.

Silicon facts, including appearance, CAS #, and molecular formula and safety data, research and properties are available for many specific states, forms and shapes on the product pages listed to the left. Elemental or metallic forms include pellets, rod, wire and granules for evaporation source material purposes.Nanoparticles and nanopowdersprovide ultra high surface area which nanotechnology research and recent experiments demonstrate function to create new and unique properties and benefits. 

Oxides are available in forms including powders and dense pellets for such uses as optical coating and thin film applications. Oxides tend to be insoluble. Fluorides are another insoluble form for uses in which oxygen is undesirable such as metallurgy, chemical and physical vapor deposition and in some optical coatings. Silicon is available in soluble forms including chlorides, nitrates and acetates. These compounds are also manufactured as solutions at specified stoichiometries. 

Silicon is a Block D, Group 14, Period 3 element. The number of electrons in each of Silicon‘s shells is 2, 8, 4 and its electronic configuration is [Ne] 3s2 3p2. In its elemental form silicon‘s CAS number is 7440-21-3. The silicon atom has a radius of and it‘s Van der Waals radius is Silicon is not toxic but can cause chronic respiratory problems if inhaled as a fine silica or silicate dust. Asbestos silicates are carcinogenic. 

All elemental metals, compounds and solutions may be synthesized in ultra high purity (e.g. 99.999%) for laboratory standards, advanced electronic, thin fillm deposition using sputtering targets and evaporation materials, metallurgy and optical materials and other high technology applications. Information is provided for stable (non-radioactive) isotopesOrgano-Metallic Silicon compounds are soluble in organic or non-aqueous solvents. See Analytical Services for information on available certified chemical and physical analysis techniques including MS-ICP, X-Ray Diffraction, PSD and Surface Area (BET) analysis. 

Silicon was first discovered by Jons Berzelius in 1823. The name Silicon originates from the Latin word "silex" which means flint or hard stone.

Abundance. The following table shows the abundance of silicon and each of its naturally occurringisotopes on Earth along with the atomic mass for each isotope.
Isotope Atomic Mass % Abundance on Earth
Si-28 27.976926533 92.23
Si-29 28.97649472 4.67
Si-30 29.97377022 3.10

The following table shows the abundance of Silicon present in the human body and in the universe scaled to parts per billion (ppb) by weight and by atom:
  Typical Human Body Universe
by Weight 260000 ppb 700000 ppb
by Atom 58000 ppb 30000 ppb

Safety Data and Biological Role. The safety data for silicon metalnanoparticles and its compounds can vary widely depending on the form. For potential hazard information, toxicity, and road, sea and air transportation limitations, such as DOT Hazard Class, DOT Number, EU Number, NFPA Health rating and RTECS Class, please see the specific material or compound referenced in the left margin. Siliconcompounds are used by diatoms, and some protoza, sponges and plants as a structural material. 

Ionization Energy. The ionization energy for silicon (the least required energy to release a single electron from the atom in it‘s ground state in the gas phase) is stated in the following table:
1st Ionization Energy 786.52 kJ mol-1
2nd Ionization Energy 1577.15 kJ mol-1
3rd Ionization Energy 3231.61 kJ mol-1

Conductivity. As to silicon‘s electrical and thermal conductivity, the electrical conductivity measured as to electrical resistivity @ 20 ?C is 10 μΩcm and its electronegativities (or its ability to draw electrons relative to other elements) is 1.9. The thermal conductivity of silicon is 148 W m-1 K-1. 

Thermal Properties. The melting point and boiling point for silicon are stated below. The following chart sets forth the heat of fusion, heat of vaporization and heat of atomization.
Heat of Fusion 39.6 kJ mol-1
Heat of Vaporization 383.3 kJ mol-1
Heat of Atomization 451.29 kJ mol-1

Formula Atomic Number Molecular Weight Electronegativity (Pauling) Density Melting Point Boiling Point Vanderwaals radius Ionic radius Energy of first ionization
Si 14 28.0855 g.mol -1 1.8 2.33 at 20 °C 1410 °C 3265 °C 0.132 nm 0.271 nm (-4) ; 0.041 (+4) 786.3 kJ.mol-1