Krom

24
Cr
Grupp
6
Period
4
Block
d
Protoner
Elektroner
Neutroner
24
24
28
Generella Egenskaper
Atomnummer
24
Atommassa
51,9961
Masstal
52
Kategori
Övergångsmetaller
Färg
Silver
Radioaktiv
Nej
From the Greek word chroma, color
Kristallstruktur
Rymdcentrerat kubisk
Historia
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.
Elektroner per skal
2, 8, 13, 1
Elektronkonfiguration
[Ar] 3d5 4s1
Cr
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Fysikaliska Egenskaper
Aggregationstillstånd
Fast
Densitet
7,15 g/cm3
Smältpunkt
2180,15 K | 1907 °C | 3464,6 °F
Kokpunkt
2944,15 K | 2671 °C | 4839,8 °F
Smältvärme
20,5 kJ/mol
Ångbildningsvärme
339 kJ/mol
Specifik värmekapacitet
0,449 J/g·K
Abundance in Earth's crust
0,014%
Abundance in Universe
0,0015%
High
Bildkrediter: 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 Number
7440-47-3
PubChem CID Number
23976
Atomära Egenskaper
Atomradie
128 pm
Kovalent radie
139 pm
Elektronegativitet
1,66 (Paulingskalan)
Jonisationspotential
6,7665 eV
Molvolym
7,23 cm3/mol
Värmeledningsförmåga
0,937 W/cm·K
Oxidationstillstånd
-2, -1, 1, 2, 3, 4, 5, 6
Användningsområden
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
Isotoper
Stabila isotoper
50Cr, 52Cr, 53Cr, 54Cr
Instabila isotoper
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr