Chrom

24
Cr
Gruppe
6
Periode
4
Block
d
Protonen
Elektronen
Neutronen
24
24
28
Generelle Eigenschaften
Ordnungszahl
24
Atommasse
51,9961
Massenzahl
52
Kategorie
Übergangsmetalle
Farbe
Silber
Radioaktiv
Nein
Aus dem Griechischen chroma (Farbe)
Kristallstruktur
Kubisch raumzentriert
Geschichte
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.
Elektronen pro Schale
2, 8, 13, 1
Elektronenkonfiguration
[Ar] 3d5 4s1
Cr
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Physikalische Eigenschaften
Aggregatzustand
Fest
Dichte
7,15 g/cm3
Schmelzpunkt
2180,15 K | 1907 °C | 3464,6 °F
Siedepunkt
2944,15 K | 2671 °C | 4839,8 °F
Schmelzwärme
20,5 kJ/mol
Verdampfungswärme
339 kJ/mol
Spezifische Wärmekapazität
0,449 J/g·K
Häufigkeit in der Erdkruste
0,014%
Häufigkeit im Universum
0,0015%
High
Danksagungen für Bilder: 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 Number
23976
Atomeigenschaften
Atomradius
128 pm
Kovalenter Radius
139 pm
Elektronegativität
1,66 (Pauling-Skala)
Ionisierungsenergie
6,7665 eV
Molares Volumen
7,23 cm3/mol
Wärmeleitfähigkeit
0,937 W/cm·K
Oxidationszustände
-2, -1, 1, 2, 3, 4, 5, 6
Anwendung
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.
In larger amounts, chromium can be toxic and carcinogenic
Isotope
Stabile Isotope
50Cr, 52Cr, 53Cr, 54Cr
Instabile Isotope
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr