Chróm
24
Cr
Skupina
6
Perióda
4
Orbitál
d
Protóny
Elektróny
Neutróny
24
24
28
Hlavné vlastnosti
Protónové číslo
24
Atómová hmotnosť
51,9961
Hmotnostné číslo
52
Kategória
Prechodné prvky
Farba
Strieborná
Rádioaktívny
Nie
From the Greek word chroma, color
Kryštálová sústava
Centrovaný kockový
História
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.
Elektróny v obale
2, 8, 13, 1
Elektrónová konfigurácia
[Ar] 3d5 4s1
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Fyzikálne vlastnosti
Skupenstvo
Tuhé látky
Hustota
7,15 g/cm3
Teplota topenia
2180,15 K | 1907 °C | 3464,6 °F
Teplota varu
2944,15 K | 2671 °C | 4839,8 °F
Skupenské teplo topenia
20,5 kJ/mol
Skupenské teplo varu
339 kJ/mol
Tepelná kapacita
0,449 J/g·K
Množstvo v zemskej kôre
0,014%
Množstvo vo vesmíre
0,0015%
Zdroje obrázkov: 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
Registračné číslo CAS
7440-47-3
PubChem CID číslo
23976
Atómové vlastnosti
Atómový polomer
128 pm
Kovalentný polomer
139 pm
Elektronegativita
1,66 (Paulingova stupnica)
Ionizačný potenciál
6,7665 eV
Atómový objem
7,23 cm3/mol
Tepelná vodivosť
0,937 W/cm·K
Oxidačné stavy
-2, -1, 1, 2, 3, 4, 5, 6
Aplikácie
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
Izotopy
Stabilné izotopy
50Cr, 52Cr, 53Cr, 54CrNestabilné izotopy
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr