Chromium

Crchromechromium(III)trivalent chromiumchrome oreChromium IIICr 2 Dichromium 51 Crchro
Chromium is a chemical element with the symbol Cr and atomic number 24.wikipedia
1,470 Related Articles

Stainless steel

stainless-steelstainlessstainless steels
Chromium is the main additive in stainless steel, to which it adds anti-corrosive properties.
In metallurgy, stainless steel, also known as inox steel or inox from French inoxydable (inoxidizable), is a steel alloy, with a minimum of 11% chromium content by mass and a maximum of 1.2% carbon by mass.

Group 6 element

group 66group 6 elements
It is the first element in group 6.
Its members are chromium (Cr), molybdenum (Mo), tungsten (W), and seaborgium (Sg).

Chromite

chrome oreMagnesiochromitechrome
Ferrochromium alloy is commercially produced from chromite by silicothermic or aluminothermic reactions and chromium metal by roasting and leaching processes followed by reduction with carbon and then aluminium.
Chromite is a mineral that is an iron chromium oxide.

Chrome plating

chromechrome platedchrome-plated
Stainless steel and chrome plating (electroplating with chromium) together comprise 85% of the commercial use.
Chrome plating (less commonly chromium plating), often referred to simply as chrome, is a technique of electroplating a thin layer of chromium onto a metal object.

Hexavalent chromium

chromium VIchromium(VI)chromium-6
While chromium metal and Cr(III) ions are not considered toxic, hexavalent chromium (Cr(VI)) is both toxic and carcinogenic.
Hexavalent chromium (chromium(VI), Cr(VI), chromium 6) is any chemical compound that contains the element chromium in the +6 oxidation state (thus hexavalent).

Ferrochrome

ferrochromiumchromium
Ferrochromium alloy is commercially produced from chromite by silicothermic or aluminothermic reactions and chromium metal by roasting and leaching processes followed by reduction with carbon and then aluminium.
Ferrochrome, or Ferrochromium (FeCr) is a type of ferroalloy, that is, an alloy between chromium and iron, generally containing 50% to 70% chromium by weight.

Symbol (chemistry)

symbolchemical symbolchemical symbols
Chromium is a chemical element with the symbol Cr and atomic number 24.

Vanadium

Vvanadium steelV 3 Si
Chromium is the first element in the 3d series where the 3d electrons start to sink into the inert core; they thus contribute less to metallic bonding, and hence the melting and boiling points and the enthalpy of atomisation of chromium are lower than those of the preceding element vanadium. However, it still has the second highest melting point out of all the Period 4 elements, being topped by vanadium by 3 °C (5 °F) at 1910 °C (3470 °F).
Four years later, he was (erroneously) convinced by other scientists that erythronium was identical to chromium.

Transition metal

transition metalstransition elementtransition-metal
It is a steely-grey, lustrous, hard and brittle transition metal. The boiling point of 2671 °C (4840 °F), however, is comparatively lower, having the third lowest boiling point out of the Period 4 transition metals alone behind manganese and zinc.

Corundum

Al 2 O 3 C'''orundumcorindon
Its Mohs hardness is 8.5, which means that it can scratch samples of quartz and topaz, but can be scratched by corundum.
Corundum is a crystalline form of aluminium oxide typically containing traces of iron, titanium, vanadium and chromium.

Metal

metalsmetal ionsmetal ion
Chromium is also highly valued as a metal that is able to be highly polished while resisting tarnishing.
The addition of silicon will produce cast irons, while the addition of chromium, nickel and molybdenum to carbon steels (more than 10%) results in stainless steels.

Passivation (chemistry)

passivationsurface passivationpassivating
Chromium metal left standing in air is passivated, i.e. forms a thin, protective, surface layer of oxide.
Corrosion coating reduces the rate of corrosion by varying degrees, depending on the kind of base metal and its environment, and is notably slower in room-temperature air for aluminium, chromium, zinc, titanium, and silicon (a metalloid); the shell of corrosion inhibits deeper corrosion, and operates as one form of passivation.

Corrosion

corrosion resistancecorrodecorrosive
Chromium metal is of high value for its high corrosion resistance and hardness.
Stainless steel can pose special corrosion challenges, since its passivating behavior relies on the presence of a major alloying component (chromium, at least 11.5%).

Manganese

Mnmanganese oreMn 2+
The boiling point of 2671 °C (4840 °F), however, is comparatively lower, having the third lowest boiling point out of the Period 4 transition metals alone behind manganese and zinc.
53 Mn decays to 53 Cr with a half-life of 3.7 million years.

Period 4 element

fourth periodPeriod 44
The boiling point of 2671 °C (4840 °F), however, is comparatively lower, having the third lowest boiling point out of the Period 4 transition metals alone behind manganese and zinc. However, it still has the second highest melting point out of all the Period 4 elements, being topped by vanadium by 3 °C (5 °F) at 1910 °C (3470 °F).
Chromium (Cr) is an element in group 6.

Molybdenum

MomolyMolybdenum (Mo)
This occurs again later in the periodic table with other elements and their electron configurations, such as copper, niobium, and molybdenum. Chromium(VI) is a strong oxidising agent in contrast to the molybdenum(VI) and tungsten(VI) oxides.
Like chromium and some other transition metals, molybdenum forms quadruple bonds, such as in Mo 2 (CH 3 COO) 4 and [Mo 2 Cl 8 ] 4−, which also has a quadruple bond.

Aluminium

aluminumAlall-metal
Ferrochromium alloy is commercially produced from chromite by silicothermic or aluminothermic reactions and chromium metal by roasting and leaching processes followed by reduction with carbon and then aluminium.
Impurities in Al 2 O 3, such as chromium and iron, yield the gemstones ruby and sapphire, respectively.

Chromium(II) chloride

CrCl 2 CoCl 2 CrCl 2 (H 2 O) 4
Many chromium(II) compounds are known, such as the water-stable chromium(II) chloride that can be made by reducing chromium(III) chloride with zinc.
Chromium(II) chloride describes inorganic compounds with the formula CrCl 2 (H 2 O) n.

Tungsten

WwolframTungsten (W)
Chromium(VI) is a strong oxidising agent in contrast to the molybdenum(VI) and tungsten(VI) oxides.
The chemistries of tungsten and molybdenum show strong similarities to each other, as well as contrasts with their lighter congener, chromium.

Chromium(III) oxide

Cr 2 O 3 chromiachrome green
A large number of chromium(III) compounds are known, such as chromium(III) nitrate, chromium(III) acetate, and chromium(III) oxide.
It is one of the principal oxides of chromium and is used as a pigment.

Alum

AlaunAllumalum compounds
The ion has a similar radius (63 pm) to (radius 50 pm), and they can replace each other in some compounds, such as in chrome alum and alum.
The name "alum" is also used, more generally, for salts with the same formula and structure, except that aluminium is replaced by another trivalent metal ion like chromium(III), and/or sulfur is replaced by other chalcogen like selenium.

Nitric acid

nitricHNO 3 aqua fortis
Passivation can be enhanced by short contact with oxidizing acids like nitric acid.
Although chromium (Cr), iron (Fe), and aluminium (Al) readily dissolve in dilute nitric acid, the concentrated acid forms a metal-oxide layer that protects the bulk of the metal from further oxidation.

Chromium(III) chloride

chromic chlorideCrCl 3 chromium trichloride
Commercially available chromium(III) chloride hydrate is the dark green complex [CrCl 2 (H 2 O) 4 ]Cl.
Anhydrous chromium(III) chloride may be prepared by chlorination of chromium metal directly, or indirectly by carbothermic chlorination of chromium(III) oxide at 650–800 °C

Oxidizing agent

oxidizeroxidantoxidants
Chromium(VI) is a strong oxidising agent in contrast to the molybdenum(VI) and tungsten(VI) oxides.

Quintuple bond

metal-metal multiple bonding
As verified by X-ray diffraction, a Cr-Cr quintuple bond (length 183.51(4) pm) has also been described.
A quintuple bond in chemistry is an unusual type of chemical bond, first reported in 2005 for a dichromium compound.