Symbol
Th
  
Pr
  
Group Number
Not Available
  
Period Number
7
  
6
  
Block
f block
  
f block
  
Element Family
Actinide
  
Lanthanide
  
Space Group Name
P63/mmc
  
P63/mmc
  
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.
  
- Praseodymium metal is synthetically produced metal.
- Praseodymium is used as possible fuel for radioactive generators.
  
Sources
Found in Minerals, Mining
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Jöns Jakob Berzelius
  
Not Available
  
Discovery
In 1829
  
In 1885
  
Abundance
  
  
Abundance In Sun
~0.0000001 %
  
26
Abundance In Earth's Crust
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.
  
- The main use of Praseodymium include alloys. Praseodymium –Magnesium alloy is used in aircraft engines due to its high strength.
-
This metal is also used while making a permanent magnets.
  
Industrial Uses
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
  
Chemical Industry
  
Medical Uses
Dentistry, Surgical Instruments Manufacturing
  
NA
  
Other Uses
Alloys, Jewellery, Sculptures, Statues
  
Alloys
  
Biological Properties
  
  
Toxicity
Non Toxic
  
Moderately Toxic
  
Present in Human Body
Yes
  
No
  
In Blood
0.00 Blood/mg dm-3
  
33
Not Available
  
In Bone
0.02 p.p.m.
  
29
Not Available
  
Melting Point
1,750.00 °C
  
17
Boiling Point
3,130.00 °C
  
27
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silver
  
Grayish White
  
Luster
NA
  
Metallic
  
Hardness
  
  
Mohs Hardness
Not Available
  
Speed of Sound
2,490.00 m/s
  
36
2,280.00 m/s
  
40
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
Th
  
Pr
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
587.00 kJ/mol
  
99+
527.00 kJ/mol
  
99+
2nd Energy Level
1,110.00 kJ/mol
  
99+
1,020.00 kJ/mol
  
99+
3rd Energy Level
1,978.00 kJ/mol
  
99+
2,086.00 kJ/mol
  
99+
4th Energy Level
2,780.00 kJ/mol
  
99+
3,761.00 kJ/mol
  
99+
5th Energy Level
Not Available
  
5,551.00 kJ/mol
  
29
Electrochemical Equivalent
2.16 g/amp-hr
  
24
1.75 g/amp-hr
  
40
Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
  
Anti Corrosion, Ionization, Radioactive Isotopes
  
Electron Configuration
[Rn] 6d2 7s2
  
[Xe] 4f3 6s2
  
Crystal Structure
Face Centered Cubic (FCC)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
FCC-Crystal-Structure-of-Thorium.jpg#100
  
HCP-Crystal-Structure-of-Praseodymium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
140.91 amu
  
99+
Atomic Volume
19.90 cm3/mol
  
20
20.80 cm3/mol
  
15
Adjacent Atomic Numbers
  
  
Valence Electron Potential
59.30 (-eV)
  
23
42.64 (-eV)
  
99+
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
11.72 g/cm3
  
32
6.77 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 1000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Superconductor
  
Conductor
  
Resistivity
157.00 nΩ·m
  
22
Electrical Conductivity
0.07 106/cm Ω
  
31
0.01 106/cm Ω
  
99+
Electron Affinity
Not Available
  
50.00 kJ/mol
  
21
Specific Heat
0.12 J/(kg K)
  
40
0.19 J/(kg K)
  
32
Molar Heat Capacity
26.23 J/mol·K
  
30
27.20 J/mol·K
  
18
Thermal Conductivity
54.00 W/m·K
  
28
12.50 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
11.00 µm/(m·K)
  
36
6.70 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
429.00 kJ/mol
  
15
296.80 kJ/mol
  
29
Enthalpy of Fusion
15.48 kJ/mol
  
19
6.89 kJ/mol
  
99+
Enthalpy of Atomization
468.60 kJ/mol
  
15
368.00 kJ/mol
  
24
Standard Molar Entropy
27.30 J/mol.K
  
99+
73.20 J/mol.K
  
10