Хром

24
Cr
Група
6
Периода
4
блок
d
Protons
Electrons
Neutrons
24
24
28
Општи Својства
Атомски број
24
Атомска тежина
51,9961
Mass Number
52
Category
Преоден метал
Color
Silver
Radioactive
Не
From the Greek word chroma, color
Кристална структура
Body Centered Cubic
History
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.
Electrons per shell
2, 8, 13, 1
Електронска конфигурација
[Ar] 3d5 4s1
Cr
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Физички Својства
Фаза
Solid
Густина
7,15 g/cm3
Точка на топење
2180,15 K | 1907 °C | 3464,6 °F
Точка на вриење
2944,15 K | 2671 °C | 4839,8 °F
Топлина на топење
20,5 kJ/mol
Топлина на испарување
339 kJ/mol
Specific Heat Capacity
0,449 J/g·K
Abundance in Earth's crust
0,014%
Abundance in Universe
0,0015%
High
Кредити на слика: 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
Атомски Својства
Атомски полупречник
128 pm
Ковалентен полупречник
139 pm
Електронегативност
1,66 (Полингова скала)
Ionization Potential
6,7665 eV
Atomic Volume
7,23 cm3/mol
Thermal Conductivity
0,937 W/cm·K
Oxidation States
-2, -1, 1, 2, 3, 4, 5, 6
Applications
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
Isotopes
Stable Isotopes
50Cr, 52Cr, 53Cr, 54Cr
Unstable Isotopes
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr