Kromi
24
Cr
Ryhmä
6
Jakso
4
Lohko
d
Protonia
Elektronit
Neutronia
24
24
28
Yleiset ominaisuudet
Järjestysluku
24
Atomipaino
51,9961
Massaluku
52
Luokka
Siirtymäalkuaineet
Väri
Hopea
Radioaktiivisuus
Ei
From the Greek word chroma, color
Kiderakenne
Tilakeskinen kuutiollinen
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.
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.
Elektroneja elektronikuorilla
2, 8, 13, 1
Orbitaalirakenne
[Ar] 3d5 4s1
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Fyysiset ominaisuudet
Olomuoto
Kiinteä
Tiheys
7,15 g/cm3
Sulamispiste
2180,15 K | 1907 °C | 3464,6 °F
Kiehumispiste
2944,15 K | 2671 °C | 4839,8 °F
Sulamislämpö
20,5 kJ/mol
Höyrystymislämpö
339 kJ/mol
Ominaislämpökapasiteetti
0,449 J/g·K
Esiintyvyys maankuoressa
0,014%
Esiintyvyys maailmankaikkeudessa
0,0015%
Kuvalähteet: 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-numero
7440-47-3
PubChem CID-numero
23976
Atomiominaisuudet
Atomisäde
128 pm
Kovalenttisäde
139 pm
Elektronegatiivisuus
1,66 (Paulingin asteikko)
Ionisoitumispotentiaali
6,7665 eV
Moolitilavuus
7,23 cm3/mol
Lämmönjohtavuus
0,937 W/cm·K
Hapetusluvut
-2, -1, 1, 2, 3, 4, 5, 6
Käyttö
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
Isotooppi
Vakaat isotoopit
50Cr, 52Cr, 53Cr, 54CrEpävakaat isotoopit
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr