5
B
13
週期
2
p
個質子
電子
個中子
5
5
6
一般屬性
原子序數
5
標準原子質量
10.811
品質編號
11
類別
類金屬
顏色
黑色
放射性
From the Arabic word Buraq, Persian Burah
晶體結構
簡單三角
歷史
Boron compounds have been known for thousands of years, but the element was not discovered until 1808 by Sir Humphry Davy and by Gay-Lussac and Thenard.

Boron was not recognized as an element until it was isolated in 1808 by Sir Humphry Davy and by Joseph Louis Gay-Lussac and Louis Jacques Thénard.

Jöns Jakob Berzelius identified boron as an element in 1824.
每個外殼的電子
2, 3
電子排布
[He] 2s2 2p1
B
Boron is an essential nutrient for all green plants
物理性質
物態
固體
密度
2.34 g/cm3
熔點
2349.15 K | 2076 °C | 3768.8 °F
沸點
4200.15 K | 3927 °C | 7100.6 °F
熔化熱
50 kJ/mol
汽化熱
507 kJ/mol
比熱容
1.026 J/g·K
地殼豐度
0.00086%
宇宙豐度
1×10-7%
Pure
圖片來源: Images-of-elements
Pure crystalline boron, front side
CAS 編號
7440-42-8
Pubchem CID 編號
5462311
原子性質
原子半徑
90 pm
共價半徑
84 pm
電負性
2.04 (鲍林标度)
電離電位
8.298 eV
原子體積
4.6 cm3/mol
熱導率
0.274 W/cm·K
氧化態
1, 2, 3
應用
Boron oxide is used in glassmaking and ceramics.

Borax is used in making fiberglass, as a cleansing fluid, a water softener, insecticide, herbicide and disinfectant.

Boric acid is used as a mild antiseptic and as a flame retardant.

Boron shielding is used as a control for nuclear reactors.
Elemental boron, boron oxide, boric acid, borates and many organoboron compounds are non-toxic
同位素
穩定同位素
10B, 11B
不穩定同位素
7B, 8B, 9B, 12B, 13B, 14B, 15B, 16B, 17B, 18B, 19B