Хром
24
Cr
Група
6
Периода
4
Блок
d
Протони
Електрони
Неутрони
24
24
28
Општа својства
Атомски број
24
Атомска маса
51,9961
Масени број
52
Категорија
Прелазни метали
Боја
Сребрена
Радиоактиван
Не
From the Greek word chroma, color
Кристална структура
Просторноцентрична Кубична
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 по љусци
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
Физичка својства
Стање
Чвсрто
Густина
7,15 g/cm3
Температура топљења
2180,15 K | 1907 °C | 3464,6 °F
Температура кључања
2944,15 K | 2671 °C | 4839,8 °F
Топлота топљења
20,5 kJ/mol
Топлота испаравања
339 kJ/mol
Специфична топлота
0,449 J/g·K
Заступљеност у Земљиној кори
0,014%
Заступљеност у Космосу
0,0015%
Захвалности за слике: 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
ПубЦхем ЦИД број
23976
Атомска својства
Атомски радијус
128 pm
Ковалентни радијус
139 pm
Електронегативност
1,66 (Полингова скала)
Јонизујући потенцијал
6,7665 eV
Молска запремина
7,23 cm3/mol
Топлотна проводљивост
0,937 W/cm·K
Оксидациона стања
-2, -1, 1, 2, 3, 4, 5, 6
Примена
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