クロム

24
Cr
6
周期
4
ブロック
d
陽子
電子
中性子
24
24
28
一般特性
原子番号
24
原子量
51.9961
質量数
52
カテゴリ
遷移元素
銀色
放射性
いいえ
From the Greek word chroma, color
結晶構造
体心立方格子
歴史
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.
電子殻
2, 8, 13, 1
電子配置
[Ar] 3d5 4s1
Cr
Chromium oxide was used by the Chinese in the Qin dynasty over 2,000 years ago
物理特性
固体
密度
7.15 g/㎝3
融点
2180.15 K | 1907 °C | 3464.6 °F
沸点
2944.15 K | 2671 °C | 4839.8 °F
融解熱
20.5 kJ/mol
蒸発熱
339 kJ/mol
熱容量
0.449 J/g·K
地殻中における存在比
0.014%
宇宙空間における存在比
0.0015%
High
画像の出典: 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登録番号
7440-47-3
PubChem CID Number
23976
原子特性
原子半径
128 pm
共有結合半径
139 pm
電気陰性度
1.66 (ポーリングの値)
イオン化エネルギー
6.7665 eV
モル体積
7.23 ㎝3/mol
熱伝導率
0.937 W/㎝·K
酸化数
-2, -1, 1, 2, 3, 4, 5, 6
用途
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
同位体
安定同位体
50Cr, 52Cr, 53Cr, 54Cr
不安定同位体
42Cr, 43Cr, 44Cr, 45Cr, 46Cr, 47Cr, 48Cr, 49Cr, 51Cr, 55Cr, 56Cr, 57Cr, 58Cr, 59Cr, 60Cr, 61Cr, 62Cr, 63Cr, 64Cr, 65Cr, 66Cr, 67Cr