Symbol
Pa
  
Hf
  
Group Number
Not Available
  
Period Number
7
  
6
  
Block
f block
  
d block
  
Element Family
Actinide
  
Transition Metal
  
Space Group Name
I4/mmm
  
P63/mmc
  
Interesting Facts
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
  
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
Sources
Found in Uranium Ores, Mining, Ores of metals
  
By-product Zirconium Refining
  
History
  
  
Who Discovered
William Crookes
  
Dirk Coster and George de Hevesy
  
Discovery
In 1900
  
In 1922
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
~0.0000001 %
  
26
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Uses & Benefits
- Currently known uses of Protactinium metal are limited to research purpose only.
  
- It has an ability to absorb neutrons and hence it is used to make control rods in nuclear submarines. And this metal is also used in Plasma welding torches.
-
It alloys with iron, titanium and niobium are very useful.
  
Industrial Uses
NA
  
Ammunition Industry
  
Medical Uses
NA
  
NA
  
Other Uses
NA
  
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Toxic
  
Present in Human Body
No
  
No
  
In Blood
0.00 Blood/mg dm-3
  
37
Not Available
  
In Bone
0.00 p.p.m.
  
36
Not Available
  
Melting Point
1,568.00 °C
  
21
2,150.00 °C
  
10
Boiling Point
4,027.00 °C
  
12
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Gray
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
1,450.00 MPa
  
6
Vickers Hardness
Not Available
  
1,520.00 MPa
  
5
Speed of Sound
Not Available
  
3,010.00 m/s
  
27
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Pa
  
Hf
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
568.00 kJ/mol
  
99+
658.50 kJ/mol
  
40
2nd Energy Level
1,128.00 kJ/mol
  
99+
1,440.00 kJ/mol
  
99+
3rd Energy Level
1,814.00 kJ/mol
  
99+
2,250.00 kJ/mol
  
99+
4th Energy Level
2,991.00 kJ/mol
  
99+
3,216.00 kJ/mol
  
99+
Electrochemical Equivalent
1.72 g/amp-hr
  
99+
1.66 g/amp-hr
  
99+
Electron Work Function
Not Available
  
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
  
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Rn] 5f2 6d1 7s2
  
[Xe] 4f14 5d2 6s2
  
Crystal Structure
Tetragonal (TETR)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
TETR-Crystal-Structure-of-Protactinium.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
15.00 cm3/mol
  
34
13.60 cm3/mol
  
38
Adjacent Atomic Numbers
  
  
Valence Electron Potential
92.00 (-eV)
  
11
81.00 (-eV)
  
16
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
15.37 g/cm3
  
20
13.31 g/cm3
  
26
Density When Liquid (at m.p.)
Not Available
  
12.00 g/cm3
  
12
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Shear Modulus
Not Available
  
Bulk Modulus
Not Available
  
Young's Modulus
Not Available
  
Poisson Ratio
Not Available
  
Other Mechanical Properties
Unknown
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
177.00 nΩ·m
  
21
331.00 nΩ·m
  
14
Electrical Conductivity
0.05 106/cm Ω
  
34
0.03 106/cm Ω
  
39
Electron Affinity
Not Available
  
0.00 kJ/mol
  
40
Specific Heat
0.12 J/(kg K)
  
40
0.14 J/(kg K)
  
37
Molar Heat Capacity
Not Available
  
25.73 J/mol·K
  
36
Thermal Conductivity
47.00 W/m·K
  
32
23.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
9.90 µm/(m·K)
  
40
5.90 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
Not Available
  
661.10 kJ/mol
  
5
Enthalpy of Fusion
12.34 kJ/mol
  
28
25.10 kJ/mol
  
8
Enthalpy of Atomization
Not Available
  
703.00 kJ/mol
  
5
Standard Molar Entropy
198.10 J/mol.K
  
1
43.60 J/mol.K
  
34