CAS Number7440-47-3
PubChem CID23976
Atomic Radius128
Atomic Volume7.23
Atomic Weight51.9961
Boiling Point2671
Bulk Modulus
CategoryTransition metals
Crystal StructureBody Centered Cubic
Covalent Radius139
Electrical Resistivity
Electron Configuration[Ar] 3d5 4s1
Electrons per shell2, 8, 13, 1
Heat of Fusion20.5
Heat of Vaporization339
Ionization Potential6.7665
Magnetic Ordering
Magnetic Susceptibility
Mass Number24
Melting Point1907
Atomic Number52
Oxidation States-2, -1, 1, 2, 3, 4, 5, 6
Poisson Ratio
Shear Modulus
Specific Heat Capacity0.449
Thermal Conductivity0.937
Van der Waals radius
Young's Modulus
Abundance in Earth's crust0.014%
Abundance in Universe0.0015%
Cr Kheromiamo 24 51.9961 6 4 d 24 1857.0 2672.0 [Ar] 3d5 4s1 2 8 13 1 7.19 0.014% Silver Cubic: Body centered 1.7 1.65 {"1":"652.9","2":"1590.6","3":"2987","4":"4743","5":"6702","6":"8744.9","7":"15455","8":"17820","9":"20190","10":"23580","11":"26130","12":"28750","13":"34230","14":"37066","15":"97510","16":"105800","17":"114300","18":"125300","19":"134700","20":"144300","21":"157700","22":"166090","23":"721870","24":"761733"} 653 64.3 127 +3,2,6 1.3 7.23 20.0 339.5 0.449 93.7 393.K 0 Solid, Antiferromagnetic, Conductor, TransitionMetal, Metal, Stable, Natural KROH-mi-em Very hard, crystalline, steel-gray metal. The pure metal has a blue-white color. It is hard, brittle and corrsion-resistant at normal temperatures. Used to make stainless steel. It gives the color to rubies and emeralds. Iron-nickel-chromium alloys in various percentages yield an incredible variety of the most important metals in modern technology. Chromite [Fe,Mg(CrO4)] is its most important mineral. Produced commercially by heating its ore in the presence of silicon or aluminium. lzRb4zmGvNU Chromium
In 1800, Sir Humphry Davy thought silica to be a compound and not an element; but in 1811, Gay Lussac and Louis Jacques Thénard probably prepared impure amorphous silicon by heating potassium with silicon tetrafluoride.

In 1824 Jöns Jakob Berzelius prepared amorphous silicon by the same general method.

Henri Deville in 1854 first prepared crystalline silicon, the second allotropic form of the element. From the Latin word silex, silicis, flint 24 1797 Louis-Nicholas Vauquelin France From the Greek word "chroma" meaning "colour", named for the many coloured compounds known for chromium.

Isotopes of Silicon

Standard Atomic Weight


Stable Isotopes

50Cr 52Cr 53Cr 54Cr

Unstable Isotopes

42Cr 43Cr 44Cr 45Cr 46Cr 47Cr 48Cr 49Cr 51Cr 55Cr 56Cr 57Cr 58Cr 59Cr 60Cr 61Cr 62Cr 63Cr 64Cr 65Cr 66Cr 67Cr

If breathed in as a fine silica/silicate dust, it may cause chronic respiratory problems
Silicon also has the unusual property that it expands as it freezes
In the form of sand and clay it is used to make concrete and brick; it is a useful refractory material for high-temperature work, and in the form of silicates it is used in making enamels, pottery, etc.

Silica, as sand, is a principal ingredient of glass.

Silicon chips are the basis of modern electronic and computing.

Silicon carbide, more commonly called carborundum is used in abrasives.