セレン

34
Se
16
周期
4
ブロック
p
陽子
電子
中性子
34
34
45
一般特性
原子番号
34
原子量
78.96
質量数
79
カテゴリ
非金属元素
灰色
放射性
いいえ
From the Greek word Selene, moon
結晶構造
単純 単斜晶
歴史
Selenium was first observed in about the year 1300 by the alchemist Arnold of Villanova.

Selenium was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn who noted the similarity of the new element to the previously-known tellurium.

In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light.
電子殻
2, 8, 18, 6
電子配置
[Ar] 3d10 4s2 4p4
Se
Selenium deficiency in animals can lead to slow growth
物理特性
固体
密度
4.809 g/㎝3
融点
494.15 K | 221 °C | 429.8 °F
沸点
958.15 K | 685 °C | 1265 °F
融解熱
5.4 kJ/mol
蒸発熱
26 kJ/mol
熱容量
0.321 J/g·K
地殻中における存在比
5×10-6%
宇宙空間における存在比
3×10-6%
Ultrapure
画像の出典: Images-of-elements
Ultrapure black, amorphous selenium
CAS登録番号
7782-49-2
PubChem CID Number
6326970
原子特性
原子半径
120 pm
共有結合半径
120 pm
電気陰性度
2.55 (ポーリングの値)
イオン化エネルギー
9.7524 eV
モル体積
16.45 ㎝3/mol
熱伝導率
0.0204 W/㎝·K
酸化数
-2, 2, 4, 6
用途
Selenium is used in the glass industry to decolorize glass and to make red-colored glasses and enamels.

It is used as a catalyst in many chemical reactions.

It is also used as a photographic toner, and as an additive to stainless steel.

Selenium sulfide is used in anti-dandruff shampoos.
Many of selenium's compounds, such as selenates and selenites, are highly toxic
同位体
安定同位体
74Se, 76Se, 77Se, 78Se, 80Se
不安定同位体
65Se, 66Se, 67Se, 68Se, 69Se, 70Se, 71Se, 72Se, 73Se, 75Se, 79Se, 81Se, 82Se, 83Se, 84Se, 85Se, 86Se, 87Se, 88Se, 89Se, 90Se, 91Se, 92Se, 93Se, 94Se