Хром
24
Cr
Група
6
Периода
4
блок
d
Протони
Електрони
Неутрони
24
24
28
Општи Својства
Атомски број
24
Атомска тежина
51,9961
Масен број
52
Категорија
Преоден метал
Боја
Сребро
Радиоактивно
Не
From the Greek word chroma, color
Кристална структура
Телоцентрирана кубна
Историја
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.
Електрони на орбитала
2, 8, 13, 1
Електронска конфигурација
[Ar] 3d5 4s1
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
Физички Својства
Фаза
Цврста состојба
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
Специфичен топлински капацитет
0,449 J/g·K
Обилност во Земјината кора
0,014%
Обилност во Универзумот
0,0015%
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 број
7440-47-3
PubChem CID број
23976
Атомски Својства
Атомски полупречник
128 pm
Ковалентен полупречник
139 pm
Електронегативност
1,66 (Полингова скала)
Јонизациски потенцијал
6,7665 eV
Атомски волумен
7,23 cm3/mol
Топлинска спроводливост
0,937 W/cm·K
Оксидациски состојби
-2, -1, 1, 2, 3, 4, 5, 6
Примени
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
Изотопи
Стабилни изотопи
50Cr, 52Cr, 53Cr, 54CrНестабилни изотопи
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr