Chroom
24
Cr
Groep
6
Periode
4
Blok
d
Protonen
Elektronen
Neutronen
24
24
28
Algemene Eigenschappen
Atoomnummer
24
Atomair gewicht
51,9961
Massa Getal
52
Categorie
Overgangsmetalen
Kleur
Zilver
Radioactief
Nee
Van het Griekse woord chroma, kleur
Kristalstructuur
Ruimtelijk-gecentreerde Kubus
Historie
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.
Eletronen per schil
2, 8, 13, 1
Electronconfiguratie
[Ar] 3d5 4s1
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Fysieke Eigenschappen
Fase
Vast
Dichtheid
7,15 g/cm3
Smeltpunt
2180,15 K | 1907 °C | 3464,6 °F
Kookpunt
2944,15 K | 2671 °C | 4839,8 °F
Fusiewarmte
20,5 kJ/mol
Verdampingswarmte
339 kJ/mol
Specifieke Warmtecapaciteit
0,449 J/g·K
Overvloedig aanwezig in de aardkorst
0,014%
Overvloedig aanwezig in het universum
0,0015%
Verdiensten voor afbeeldingen: 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-nummer
7440-47-3
PubChem CID nummer
23976
Atoomeigenschappen
Atoomstraal
128 pm
Covalentiestraal
139 pm
Electronegativiteit
1,66 (Pauling schaal)
Ionisatiepotentiaal
6,7665 eV
Atoomvolume
7,23 cm3/mol
Thermische geleiding
0,937 W/cm·K
Oxidatietoestanden
-2, -1, 1, 2, 3, 4, 5, 6
Toepassingen
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
Isotopen
Stabiele isotopen
50Cr, 52Cr, 53Cr, 54CrInstabiele isotopen
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr