91
Pa
無法計量
週期
7
f
個質子
電子
個中子
91
91
140
一般屬性
原子序數
91
標準原子質量
231.03588
品質編號
231
類別
錒系元素
顏色
銀色
放射性
From the Greek protos meaning first
晶體結構
Centered Tetragonal
歷史
In 1900, William Crookes isolated protactinium as an intensely radioactive material from uranium

Protactinium was first identified in 1913 by Kasimir Fajans and Oswald Helmuth Göhring in Germany.

A more stable isotope of protactinium was discovered in 1917 by Otto Hahn and Lise Meitner at the Kaiser Wilhelm Institute in Berlin.
每個外殼的電子
2, 8, 18, 32, 20, 9, 2
電子排布
[Rn] 5f2 6d1 7s2
Pa
Protactinium is one of the rarest and most expensive naturally occurring elements
物理性質
物態
固體
密度
15.37 g/cm3
熔點
1841.15 K | 1568 °C | 2854.4 °F
沸點
4300.15 K | 4027 °C | 7280.6 °F
熔化熱
15 kJ/mol
汽化熱
470 kJ/mol
比熱容
-
地殼豐度
9.9×10-13%
宇宙豐度
無法計量
Illustration
圖片來源: Images-of-elements
Illustration of protactinium
CAS 編號
7440-13-3
Pubchem CID 編號
無法計量
原子性質
原子半徑
163 pm
共價半徑
200 pm
電負性
1.5 (鲍林标度)
電離電位
5.89 eV
原子體積
15.0 cm3/mol
熱導率
0.47 W/cm·K
氧化態
3, 4, 5
應用
Owing to its scarcity, high radioactivity and high toxicity, there are currently no uses for protactinium outside of scientific research.

With the advent of highly sensitive mass spectrometers, an application of 231Pa as a tracer in geology and paleoceanography has become possible.

Protactinium-231 combined with the thorium-230 can be used to date marine sediments.
Protactinium is toxic and highly radioactive
同位素
穩定同位素
-
不穩定同位素
212Pa, 213Pa, 214Pa, 215Pa, 216Pa, 217Pa, 218Pa, 219Pa, 220Pa, 221Pa, 222Pa, 223Pa, 224Pa, 225Pa, 226Pa, 227Pa, 228Pa, 229Pa, 230Pa, 231Pa, 232Pa, 233Pa, 234Pa, 235Pa, 236Pa, 237Pa, 238Pa, 239Pa, 240Pa