Symbol	Pa	Atomic radius: pm	161	Fusion: kJ/Mole	12.34
Name	Protactinium	Ionic radius: pm	(+5)78	Boiling point: °C	-
Atomic number	91	Electron affinity	-	Melting point: °C	1572
Atomic weight	231.0	1st  ion potential	5.89	Specific Heat Cap: J/(g K)	-
Classification	Trans metal	Natural form	Solid	Thermal Cond: W/(cm K)	-
Configuration	[Rn]5f26d17s2	Crystal structure	Tetra	Electrical Cond	0.0529
Oxidation states	4,5	Density	14.4	Abundance: mg/kg-crust	<0.001
Electronegativity	1.5	Vaporization: kJ/Mole	481.0
The first isotope, protactinium-234, was discovered in 1913 by Kasimir Fajans and O.H. Göhring.  The long-lived isotope, protactinium-231, was discovered in 1917 independently by Otto Hahn and Lise Meitner.			Uses - non known uses