The Element Protactinium


Protactinium is a silver metallic element that belongs to the actinide group. It is superconductive at low temperatures and is known to retain its bright metallic luster in air for a longer time. Protactinium can be known as one of the most rarest and expensive elements that occurs naturally. However, it is a dangerous toxic thus, requires precautions when handling.

It is found in pitchblende and ores from some areas of the Dominican Republic of Congo. Due to its rarity and expense, currently there are no industrial uses associated with protactinium except for basic research.

Atomic Number & Chemical Properties


Element Basics:

Chemical Symbol: Pa
Atomic Number: 91
Atomic Weight: 231.03588
Element Classification: Radioactive Rare Earth Element (Actinide Series)
Discovered By: Fredrich Soddy, John Cranston, Otto Hahn, Lise Meitner
Date of Discovery: 1917 (England/France)
Origin of Name: Greek: proto and actinium (parent of actinium); it forms actinium when it radioactively decays.

How to Recognize it at a Party:

Silvery-white, radioactive metal

Seriously Atomic Information:

Density (g/cc): 15.37
Melting Point (°K): 2113
Boiling Point (°K): 4300
Atomic Radius (pm): 161
Atomic Volume (cc/mol): 15.0
Covalent Radius (pm): n/a
Ionic Radius: 89 (+5e) 113 (+3e)
Pauling Negativity Number: 1.5
First Ionizing Energy (kJ/mol): n/a
Oxidation States: 5, 4
Electronic Configuration: [Rn] 5f2 6d1 7s2

Getting Intimate with Protactinium:

Lattice Structure: Tetragonal (TET)
Lattice Constant (Å): 3.920
Lattice C/A Ratio: n/a
Specific Heat (@20°C J/g mol): 0.121
Fusion Heat (kJ/mol): 16.7
Evaporation Heat (kJ/mol): 481.2
Thermal Conductivity (@25°C W/m K):
Debye Temperature (°K): n/a


Society's Questions About Protactinium:

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