Samarium Thorium Comparison
Periodic Table
Symbol
Sm
Th
Group Number
Not Available
0
18
Period Number
6
7
Block
f block
f block
Element Family
Lanthanide
Actinide
CAS Number
7440199
99+
7440326
99+
Space Group Name
R_ 3m
P63/mmc
Space Group Number
166.00
6
194.00
5
Facts
Interesting Facts
- Samarium metals helps stimulating body metabolism.
- Samarium metals was 1st observed by Jean Charles Galissard de Marignac in Dydimia in 1853.
- 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
Found in Minerals, Mining, Ores of Minerals
Found in Minerals, Mining
History
Who Discovered
Lecoq de Boisbaudran
Jöns Jakob Berzelius
Discovery
In 1879
In 1829
Abundance
Abundance In Universe
5 * 10-7 %
19
3 * 10-4 %
9
Abundance In Sun
~0.0000001 %
26
~0.0004 %
9
Abundance In Meteorites
0.00 %
37
0.05 %
11
Abundance In Earth's Crust
0.00 %
29
0.66 %
7
Abundance In Oceans
0.00 %
40
0.00 %
15
Uses
Uses & Benefits
- Magnets of Samarium cobalt alloy are stronger than that of Iron and hence, they are used in microwave application.
- Samarium metal also used in optical lasers and infrared absorbing glasses and as a neutron absorber.
- 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
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
Medical Uses
NA
Dentistry, Surgical Instruments Manufacturing
Other Uses
Alloys, In Nuclear Reactors
Alloys, Jewellery, Sculptures, Statues
Biological Properties
Toxicity
Slightly Toxic
Non Toxic
Present in Human Body
Yes
Yes
In Blood
0.01 Blood/mg dm-3
22
0.00 Blood/mg dm-3
33
In Bone
Not Available
0.02 p.p.m.
29
Physical Properties
Melting Point
1,072.00 °C
99+
1,750.00 °C
17
Boiling Point
1,900.00 °C
99+
4,790.00 °C
8
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silver
Luster
Lustrous
NA
Hardness
Mohs Hardness
Not Available
3.00
12
Brinell Hardness
441.00 MPa
27
390.00 MPa
29
Vickers Hardness
412.00 MPa
24
295.00 MPa
29
Speed of Sound
2,130.00 m/s
99+
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 Properties
Chemical Formula
Sm
Th
Isotopes
Known Isotopes
30
9
28
11
Electronegativity
Pauling Electronegativity
1.17
40
1.30
32
Allred Rochow Electronegativity
1.07
32
1.11
29
Electropositivity
Pauling Electropositivity
2.83
14
2.70
22
Ionization Energies
1st Energy Level
544.50 kJ/mol
99+
587.00 kJ/mol
99+
2nd Energy Level
1,070.00 kJ/mol
99+
1,110.00 kJ/mol
99+
3rd Energy Level
2,260.00 kJ/mol
99+
1,978.00 kJ/mol
99+
4th Energy Level
3,990.00 kJ/mol
37
2,780.00 kJ/mol
99+
Electrochemical Equivalent
1.87 g/amp-hr
34
2.16 g/amp-hr
24
Electron Work Function
2.70 eV
99+
3.41 eV
32
Other Chemical Properties
Ionization, Radioactive Isotopes
Corrosion, Ionization, Radioactive Isotopes, Radioactivity
Atomic Properties
Atomic Number
62
99+
90
28
Electron Configuration
[Xe] 4f6 6s2
[Rn] 6d2 7s2
Crystal Structure
Rhombohedral (RHO)
Face Centered Cubic (FCC)
Crystal Lattice
RHO-Crystal-Structure-of-Samarium.jpg#100
FCC-Crystal-Structure-of-Thorium.jpg#100
Atom
Number of Protons
62
99+
90
28
Number of Neutrons
88
39
142
15
Number of Electrons
62
99+
90
28
Radius of an Atom
Atomic Radius
180.00 pm
14
179.80 pm
15
Covalent Radius
198.00 pm
13
206.00 pm
7
Van der Waals Radius
229.00 pm
20
237.00 pm
15
Atomic Weight
150.36 amu
99+
232.04 amu
23
Atomic Volume
19.95 cm3/mol
19
19.90 cm3/mol
20
Adjacent Atomic Numbers
Valence Electron Potential
44.80 (-eV)
37
59.30 (-eV)
23
Lattice Constant
362.10 pm
33
508.42 pm
14
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
7.52 g/cm3
99+
11.72 g/cm3
32
Density When Liquid (at m.p.)
7.16 g/cm3
32
Not Available
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.94 (Pa)
9
Not Available
Vapor Pressure at 2000 K
Not Available
0.00 (Pa)
22
Elasticity properties
Shear Modulus
19.50 GPa
34
31.00 GPa
21
Bulk Modulus
37.80 GPa
35
54.00 GPa
22
Young's Modulus
49.70 GPa
37
79.00 GPa
24
Poisson Ratio
0.27
19
0.27
20
Other Mechanical Properties
NA
Ductile
Magnetic Properties
Magnetic Characteristics
Specific Gravity
7.52
99+
11.70
23
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Superconductor
Resistivity
0.94 nΩ·m
99+
157.00 nΩ·m
22
Electrical Conductivity
0.01 106/cm Ω
99+
0.07 106/cm Ω
31
Electron Affinity
50.00 kJ/mol
21
Not Available
Thermal Properties
Specific Heat
0.20 J/(kg K)
31
0.12 J/(kg K)
40
Molar Heat Capacity
29.54 J/mol·K
7
26.23 J/mol·K
30
Thermal Conductivity
13.30 W/m·K
99+
54.00 W/m·K
28
Critical Temperature
Not Available
Not Available
Thermal Expansion
12.70 µm/(m·K)
30
11.00 µm/(m·K)
36
Enthalpy
Enthalpy of Vaporization
166.40 kJ/mol
99+
429.00 kJ/mol
15
Enthalpy of Fusion
8.62 kJ/mol
40
15.48 kJ/mol
19
Enthalpy of Atomization
209.00 kJ/mol
99+
468.60 kJ/mol
15
Standard Molar Entropy
69.60 J/mol.K
15
27.30 J/mol.K
99+
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