Symbol
Hf
  
Sm
  
Group Number
Not Available
  
Period Number
6
  
6
  
Block
d block
  
f block
  
Element Family
Transition Metal
  
Lanthanide
  
Space Group Name
P63/mmc
  
R_ 3m
  
Interesting Facts
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
- Samarium metals helps stimulating body metabolism.
- Samarium metals was 1st observed by Jean Charles Galissard de Marignac in Dydimia in 1853.
  
Sources
By-product Zirconium Refining
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Dirk Coster and George de Hevesy
  
Lecoq de Boisbaudran
  
Discovery
In 1922
  
In 1879
  
Abundance
  
  
Abundance In Sun
~0.0000001 %
  
26
~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.
  
- 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.
  
Industrial Uses
Ammunition Industry
  
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Alloys, In Nuclear Reactors
  
Biological Properties
  
  
Toxicity
Toxic
  
Slightly Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
Not Available
  
0.01 Blood/mg dm-3
  
22
Melting Point
2,150.00 °C
  
10
1,072.00 °C
  
99+
Boiling Point
1,900.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Silvery White
  
Luster
Metallic
  
Lustrous
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
1,450.00 MPa
  
6
Vickers Hardness
1,520.00 MPa
  
5
Speed of Sound
3,010.00 m/s
  
27
2,130.00 m/s
  
99+
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
  
Sm
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Allen Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
658.50 kJ/mol
  
40
544.50 kJ/mol
  
99+
2nd Energy Level
1,440.00 kJ/mol
  
99+
1,070.00 kJ/mol
  
99+
3rd Energy Level
2,250.00 kJ/mol
  
99+
2,260.00 kJ/mol
  
99+
4th Energy Level
3,216.00 kJ/mol
  
99+
3,990.00 kJ/mol
  
37
Electrochemical Equivalent
1.66 g/amp-hr
  
99+
1.87 g/amp-hr
  
34
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes
  
Electron Configuration
[Xe] 4f14 5d2 6s2
  
[Xe] 4f6 6s2
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Rhombohedral (RHO)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
RHO-Crystal-Structure-of-Samarium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Weight
150.36 amu
  
99+
Atomic Volume
13.60 cm3/mol
  
38
19.95 cm3/mol
  
19
Adjacent Atomic Numbers
  
  
Valence Electron Potential
81.00 (-eV)
  
16
44.80 (-eV)
  
37
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, 2 π/3
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
13.31 g/cm3
  
26
7.52 g/cm3
  
99+
Density When Liquid (at m.p.)
12.00 g/cm3
  
12
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Vapor Pressure at 2000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Malleable
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
331.00 nΩ·m
  
14
Electrical Conductivity
0.03 106/cm Ω
  
39
0.01 106/cm Ω
  
99+
Electron Affinity
0.00 kJ/mol
  
40
50.00 kJ/mol
  
21
Specific Heat
0.14 J/(kg K)
  
37
0.20 J/(kg K)
  
31
Molar Heat Capacity
25.73 J/mol·K
  
36
29.54 J/mol·K
  
7
Thermal Conductivity
23.00 W/m·K
  
99+
13.30 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
5.90 µm/(m·K)
  
99+
12.70 µm/(m·K)
  
30
Enthalpy
  
  
Enthalpy of Vaporization
661.10 kJ/mol
  
5
166.40 kJ/mol
  
99+
Enthalpy of Fusion
25.10 kJ/mol
  
8
8.62 kJ/mol
  
40
Enthalpy of Atomization
703.00 kJ/mol
  
5
209.00 kJ/mol
  
99+
Standard Molar Entropy
43.60 J/mol.K
  
34
69.60 J/mol.K
  
15