Protactinium
Symbol
Pa
Atomic Number
91
Atomic Weight
231.03588
Element Classification
Discovered By
Fredrich Soddy, John Cranston, Otto Hahn, Lise Meitner
Discovery Date
1917 (England/France)
Name Origin
Greek: proto and actinium (parent of actinium), it forms actinium when it radioactively decays.
Density (g/cc)
15.37
Melting Point (K)
2113
Boiling Point (K)
4300
Appearance
Silvery-white, radioactive metal
Atomic Radius (pm)
161
Atomic Volume (cc/mol)
15.0
Covalent Radius (pm)
n/a
Ionic Radius
89 (+5e) 113 (+3e)
Specific Heat
0.121
Fusion Heat (kJ/mol)
16.7
Evaporation Heat (kJ/mol)
481.2
Thermal Conductivity (@25°C W/m K)
n/a
Debye Temperature (K)
n/a
Pauling Negativity Number
1.5
First Ionizing Energy (kJ/mol)
n/a
Oxidation States
5, 4
Electronic Configuration
[Rn] 5f2 6d1 7s2
Lattice Structure
Tetragonal(TET)
Lattice Constant
3.920
Lattice C/A Ratio
n/a
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