Symbol
Hf
  
Th
  
Period Number
6
  
7
  
Block
d block
  
f block
  
Element Family
Transition Metal
  
Actinide
  
Space Group Name
P63/mmc
  
P63/mmc
  
Interesting Facts
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
- Thorium metal is used as an alternate option over Uranium for nuclear fuel.
- Thorium metals appearance (silvery white, soft) is somewhat similar to Lead metal.
  
Sources
By-product Zirconium Refining
  
Found in Minerals, Mining
  
History
  
  
Who Discovered
Dirk Coster and George de Hevesy
  
Jöns Jakob Berzelius
  
Discovery
In 1922
  
In 1829
  
Abundance
  
  
Abundance In Sun
~0.0000001 %
  
26
Abundance In Earth's Crust
Uses & Benefits
- 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.
  
- Thorium metal is used as an allying agent for Magnesium, It imparts greater strength and resistance to temperature.
-
compound of this metal Thorium oxide is used as an industrial catalyst.
  
Industrial Uses
Ammunition Industry
  
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
Dentistry, Surgical Instruments Manufacturing
  
Other Uses
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Alloys, Jewellery, Sculptures, Statues
  
Biological Properties
  
  
Toxicity
Toxic
  
Non Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
Not Available
  
0.00 Blood/mg dm-3
  
33
In Bone
Not Available
  
0.02 p.p.m.
  
29
Melting Point
2,150.00 °C
  
10
1,750.00 °C
  
17
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Silver
  
Luster
Metallic
  
NA
  
Hardness
  
  
Brinell Hardness
1,450.00 MPa
  
6
Vickers Hardness
1,520.00 MPa
  
5
Speed of Sound
3,010.00 m/s
  
27
2,490.00 m/s
  
36
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
Hf
  
Th
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
658.50 kJ/mol
  
40
587.00 kJ/mol
  
99+
2nd Energy Level
1,440.00 kJ/mol
  
99+
1,110.00 kJ/mol
  
99+
3rd Energy Level
2,250.00 kJ/mol
  
99+
1,978.00 kJ/mol
  
99+
4th Energy Level
3,216.00 kJ/mol
  
99+
2,780.00 kJ/mol
  
99+
Electrochemical Equivalent
1.66 g/amp-hr
  
99+
2.16 g/amp-hr
  
24
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
  
Electron Configuration
[Xe] 4f14 5d2 6s2
  
[Rn] 6d2 7s2
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Face Centered Cubic (FCC)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
FCC-Crystal-Structure-of-Thorium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
13.60 cm3/mol
  
38
19.90 cm3/mol
  
20
Adjacent Atomic Numbers
  
  
Valence Electron Potential
81.00 (-eV)
  
16
59.30 (-eV)
  
23
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
13.31 g/cm3
  
26
11.72 g/cm3
  
32
Density When Liquid (at m.p.)
12.00 g/cm3
  
12
Not Available
  
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Malleable
  
Ductile
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Superconductor
  
Resistivity
331.00 nΩ·m
  
14
157.00 nΩ·m
  
22
Electrical Conductivity
0.03 106/cm Ω
  
39
0.07 106/cm Ω
  
31
Electron Affinity
0.00 kJ/mol
  
40
Not Available
  
Specific Heat
0.14 J/(kg K)
  
37
0.12 J/(kg K)
  
40
Molar Heat Capacity
25.73 J/mol·K
  
36
26.23 J/mol·K
  
30
Thermal Conductivity
23.00 W/m·K
  
99+
54.00 W/m·K
  
28
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
5.90 µm/(m·K)
  
99+
11.00 µm/(m·K)
  
36
Enthalpy
  
  
Enthalpy of Vaporization
661.10 kJ/mol
  
5
429.00 kJ/mol
  
15
Enthalpy of Fusion
25.10 kJ/mol
  
8
15.48 kJ/mol
  
19
Enthalpy of Atomization
703.00 kJ/mol
  
5
468.60 kJ/mol
  
15
Standard Molar Entropy
43.60 J/mol.K
  
34
27.30 J/mol.K
  
99+