Symbol
Th
  
Po
  
Period Number
7
  
6
  
Block
f block
  
p block
  
Element Family
Actinide
  
Post-Transition
  
Space Group Name
P63/mmc
  
Pm-3m
  
Interesting Facts
- 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.
  
- Polonium was the first radioactive element to be discovered.
- Polonium element and its compounds are highly radioactive.
- Its alloy with Beryllium provides source of neutrons.
  
Sources
Found in Minerals, Mining
  
Mining, Ores of metals
  
History
  
  
Who Discovered
Jöns Jakob Berzelius
  
Pierre Curie and Marie Curie
  
Discovery
In 1829
  
In 1898
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~-9999 %
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
Uses & Benefits
- 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.
  
- Polonium metal has different Allotropes, it is used in antistatic devices and for research purpose.
- A 1 gram of Polonium can reach a temperature of 500°C, hence it is used as a heat source for space equipment.
  
Industrial Uses
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
  
Aerospace Industry, Ammunition Industry
  
Medical Uses
Dentistry, Surgical Instruments Manufacturing
  
NA
  
Other Uses
Alloys, Jewellery, Sculptures, Statues
  
Alloys
  
Biological Properties
  
  
Toxicity
Non Toxic
  
Highly Toxic
  
Present in Human Body
Yes
  
No
  
In Blood
0.00 Blood/mg dm-3
  
33
0.00 Blood/mg dm-3
  
37
In Bone
0.02 p.p.m.
  
29
0.00 p.p.m.
  
36
Melting Point
1,750.00 °C
  
17
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Silver
  
Luster
NA
  
NA
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
Not Available
  
Vickers Hardness
Not Available
  
Speed of Sound
2,490.00 m/s
  
36
Not Available
  
Optical Properties
  
  
Allotropes
No
  
Yes
  
α Allotropes
Not Available
  
α-polonium
  
β Allotropes
Not Available
  
β-polonium
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Th
  
Po
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
587.00 kJ/mol
  
99+
812.10 kJ/mol
  
14
2nd Energy Level
1,110.00 kJ/mol
  
99+
Not Available
  
3rd Energy Level
1,978.00 kJ/mol
  
99+
Not Available
  
4th Energy Level
2,780.00 kJ/mol
  
99+
Not Available
  
Electrochemical Equivalent
2.16 g/amp-hr
  
24
3.90 g/amp-hr
  
8
Electron Work Function
Not Available
  
Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
  
Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Rn] 6d2 7s2
  
[Xe] 4f14 5d10 6s2 6p4
  
Crystal Structure
Face Centered Cubic (FCC)
  
Monoclinic (MON)
  
Crystal Lattice
FCC-Crystal-Structure-of-Thorium.jpg#100
  
MON-Crystal-Structure-of-Polonium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
19.90 cm3/mol
  
20
22.23 cm3/mol
  
13
Adjacent Atomic Numbers
  
  
Valence Electron Potential
59.30 (-eV)
  
23
Not Available
  
Lattice Angles
π/2, π/2, π/2
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Not Available
  
Density
  
  
Density At Room Temperature
11.72 g/cm3
  
32
9.20 g/cm3
  
99+
Density When Liquid (at m.p.)
Not Available
  
Tensile Strength
Not Available
  
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
Ductile
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Nonmagnetic
  
Electrical Properties
  
  
Electrical Property
Superconductor
  
Conductor
  
Resistivity
157.00 nΩ·m
  
22
Electrical Conductivity
0.07 106/cm Ω
  
31
0.02 106/cm Ω
  
99+
Electron Affinity
Not Available
  
183.30 kJ/mol
  
3
Specific Heat
0.12 J/(kg K)
  
40
0.12 J/(kg K)
  
40
Molar Heat Capacity
26.23 J/mol·K
  
30
26.40 J/mol·K
  
28
Thermal Conductivity
54.00 W/m·K
  
28
20.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
11.00 µm/(m·K)
  
36
23.50 µm/(m·K)
  
16
Enthalpy
  
  
Enthalpy of Vaporization
429.00 kJ/mol
  
15
60.30 kJ/mol
  
99+
Enthalpy of Fusion
15.48 kJ/mol
  
19
13.00 kJ/mol
  
26
Enthalpy of Atomization
468.60 kJ/mol
  
15
134.00 kJ/mol
  
99+
Standard Molar Entropy
27.30 J/mol.K
  
99+
Not Available