Vlastnosti

CAS Number7440-47-3
PubChem CID23976
Atomový poloměr128
Molární objem7,23
Atomová hmotnost51,996
Blokd
Teplota varu2 671
Bulk Modulus
KategoriePřechodné kovy
Krystalografická soustavaKubická prostorově centrovaná
BarvaStříbrná
Kovalentní poloměr139
Hustota7,15
Electrical Resistivity
Elektronová konfigurace[Ar] 3d5 4s1
Elektronů v obalu2, 8, 13, 1
Elektronegativita1,66
Electrons24
Skupina6
Skupenské teplo tání20,5
Skupenské teplo varu339
Ionizační potenciál6,766
Magnetic Ordering
Magnetic Susceptibility
Hmotnost51,996
Mass Number24
Teplota tání1 907
NázevChrom
Neutrony28
Atomové číslo52
Oxidační čísla-2, -1, 1, 2, 3, 4, 5, 6
Perioda4
SkupenstvíPevná
Poisson Ratio
Protony24
Shear Modulus
Měrná tepelná kapacita0,449
ZnačkaCr
Tepelná vodivost0,937
Van der Waals radius
Young's Modulus
Hojnost
Hojnost v zemské kůře0.014%
Hojnost ve vesmíru0.0015%
Cr Chrom 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. Z latinského slova silex, křemík, pazourek 24 1797 Louis-Nicholas Vauquelin France From the Greek word "chroma" meaning "colour", named for the many coloured compounds known for chromium.

Izotopy křemíku

Standard Atomic Weight

51.9961(6)

Stabilní izotopy

50Cr 52Cr 53Cr 54Cr

Nestabilní izotopy

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.