Symbol
Hf
  
Re
  
Period Number
6
  
6
  
Block
d block
  
d block
  
Element Family
Transition Metal
  
Transition Metal
  
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.
  
- Chemical properties of Rhenium are similar to Manganese.
- Rhenium metal is created while refining Molybdenum.
  
Sources
By-product Zirconium Refining
  
Found in Minerals, Mining, Ores of Minerals
  
History
  
  
Who Discovered
Dirk Coster and George de Hevesy
  
Masataka Ogawa
  
Discovery
In 1922
  
In 1908
  
Abundance
  
  
Abundance In Sun
~0.0000001 %
  
26
~0.00000001 %
  
29
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.
  
- Alloys of Rhenium are used as an electric contact material. It can resist withstand arc corrosion.
- Its catalysts are used in hydrogenation of fine chemicals. Its Alloy with nickel is used to produce turbine blades.
  
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
  
Biological Properties
  
  
Toxicity
Toxic
  
Low Toxic
  
Present in Human Body
No
  
No
  
Melting Point
2,150.00 °C
  
10
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Silvery Gray
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Brinell Hardness
1,450.00 MPa
  
6
1,320.00 MPa
  
8
Vickers Hardness
1,520.00 MPa
  
5
1,350.00 MPa
  
7
Speed of Sound
3,010.00 m/s
  
27
4,700.00 m/s
  
15
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
  
Re
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
658.50 kJ/mol
  
40
760.00 kJ/mol
  
20
2nd Energy Level
1,440.00 kJ/mol
  
99+
1,260.00 kJ/mol
  
99+
3rd Energy Level
2,250.00 kJ/mol
  
99+
2,510.00 kJ/mol
  
99+
4th Energy Level
3,216.00 kJ/mol
  
99+
3,640.00 kJ/mol
  
99+
Electrochemical Equivalent
1.66 g/amp-hr
  
99+
0.99 g/amp-hr
  
99+
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 4f14 5d2 6s2
  
[Xe] 4f14 5d5 6s2
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Hexagonal Close Packed (HCP)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
BCC-Crystal-Structure-.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
13.60 cm3/mol
  
38
8.85 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
81.00 (-eV)
  
16
180.00 (-eV)
  
3
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, 2 π/3
  
Density
  
  
Density At Room Temperature
13.31 g/cm3
  
26
21.02 g/cm3
  
12
Density When Liquid (at m.p.)
12.00 g/cm3
  
12
Tensile Strength
1,070.00 MPa
  
3
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Malleable
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Paramagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
331.00 nΩ·m
  
14
193.00 nΩ·m
  
20
Electrical Conductivity
0.03 106/cm Ω
  
39
0.05 106/cm Ω
  
33
Electron Affinity
0.00 kJ/mol
  
40
14.50 kJ/mol
  
35
Specific Heat
0.14 J/(kg K)
  
37
0.13 J/(kg K)
  
39
Molar Heat Capacity
25.73 J/mol·K
  
36
25.48 J/mol·K
  
38
Thermal Conductivity
23.00 W/m·K
  
99+
48.00 W/m·K
  
31
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
5.90 µm/(m·K)
  
99+
6.20 µm/(m·K)
  
99+
Enthalpy
  
  
Enthalpy of Vaporization
661.10 kJ/mol
  
5
707.10 kJ/mol
  
3
Enthalpy of Fusion
25.10 kJ/mol
  
8
33.05 kJ/mol
  
2
Enthalpy of Atomization
703.00 kJ/mol
  
5
791.00 kJ/mol
  
2
Standard Molar Entropy
43.60 J/mol.K
  
34
36.90 J/mol.K
  
99+