Chroom
24
Cr
Groep
6
Periode
4
Blok
d
Protrone
Elektrone
Neutrone
24
24
28
Algemene Eienskappe
Atoom Nommer
24
Atoommassa
51,9961
Massa Nommer
52
Kategorie
Oorgangsmetale
Kleur
Silver
Radioaktief
Nee
From the Greek word chroma, color
Kristalstruktuur
Ligaamsgesentreerde kubieke
Geskiendenis
In 1797, Louis Nicolas Vauquelin received samples of crocoite ore.
In 1798, Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven, making him the discoverer of the element.
Vauquelin was also able to detect traces of chromium in precious gemstones, such as ruby or emerald.
In 1798, Vauquelin discovered that he could isolate metallic chromium by heating the oxide in a charcoal oven, making him the discoverer of the element.
Vauquelin was also able to detect traces of chromium in precious gemstones, such as ruby or emerald.
Elektrone per skil
2, 8, 13, 1
Elektronkonfigurasie
[Ar] 3d5 4s1
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Fisiese Eienskappe
Fase
Soliede
Digtheid
7,15 g/cm3
Smeltpunt
2180,15 K | 1907 °C | 3464,6 °F
Kookpunt
2944,15 K | 2671 °C | 4839,8 °F
Heat of Fusion
20,5 kJ/mol
Heat of Vaporization
339 kJ/mol
Spesifieke Hitte Kapasiteit
0,449 J/g·K
Oorvloed in die aardkors
0,014%
Oorvloed in die heelal
0,0015%
Beeld Krediete: Wikimedia Commons (Alchemist-hp)
High purity chromium crystals, produced by chemical transport reaction through decomposition of chromium iodides, as well as a high purity chromium cube for comparison
CAS Nommer
7440-47-3
PubChem CID Nommer
23976
Atomiese Eienskappe
Atoom radius
128 pm
Kovalente Radius
139 pm
Elektronegatiewiteit
1,66 (Pauling scale)
Ionisasie potensiaal
6,7665 eV
Atoom volume
7,23 cm3/mol
Termiese geleidingsvermoë
0,937 W/cm·K
Oksidasiestate
-2, -1, 1, 2, 3, 4, 5, 6
Toepassings
Chromium is used to harden steel, manufacture stainless steel, and form many useful alloys.
It is mostly used in plating to produce a hard, beautiful surface and to prevent corrosion.
The metal is also widely used as a catalyst.
Chromium compounds are valued as pigments for their vivid green, yellow, red and orange colors.
It is mostly used in plating to produce a hard, beautiful surface and to prevent corrosion.
The metal is also widely used as a catalyst.
Chromium compounds are valued as pigments for their vivid green, yellow, red and orange colors.
In larger amounts, chromium can be toxic and carcinogenic
Isotope
Stabiele Isotope
50Cr, 52Cr, 53Cr, 54CrOnstabiele Isotope
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr