Symbol
Hf
  
Po
  
Period Number
6
  
6
  
Block
d block
  
p block
  
Element Family
Transition Metal
  
Post-Transition
  
Space Group Name
P63/mmc
  
Pm-3m
  
Interesting Facts
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
- 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
By-product Zirconium Refining
  
Mining, Ores of metals
  
History
  
  
Who Discovered
Dirk Coster and George de Hevesy
  
Pierre Curie and Marie Curie
  
Discovery
In 1922
  
In 1898
  
Abundance
  
  
Abundance In Universe
Not Available
  
Abundance In Sun
~0.0000001 %
  
26
~-9999 %
  
Abundance In Meteorites
Not Available
  
Abundance In Earth's Crust
Not Available
  
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.
  
- 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
Ammunition Industry
  
Aerospace Industry, Ammunition Industry
  
Medical Uses
NA
  
NA
  
Other Uses
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Alloys
  
Biological Properties
  
  
Toxicity
Toxic
  
Highly Toxic
  
Present in Human Body
No
  
No
  
In Blood
Not Available
  
0.00 Blood/mg dm-3
  
37
In Bone
Not Available
  
0.00 p.p.m.
  
36
Melting Point
2,150.00 °C
  
10
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Silver
  
Luster
Metallic
  
NA
  
Hardness
  
  
Mohs Hardness
Not Available
  
Brinell Hardness
1,450.00 MPa
  
6
Not Available
  
Vickers Hardness
1,520.00 MPa
  
5
Not Available
  
Speed of Sound
3,010.00 m/s
  
27
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
Hf
  
Po
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
658.50 kJ/mol
  
40
812.10 kJ/mol
  
14
2nd Energy Level
1,440.00 kJ/mol
  
99+
Not Available
  
3rd Energy Level
2,250.00 kJ/mol
  
99+
Not Available
  
4th Energy Level
3,216.00 kJ/mol
  
99+
Not Available
  
Electrochemical Equivalent
1.66 g/amp-hr
  
99+
3.90 g/amp-hr
  
8
Electron Work Function
Not Available
  
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Ionization, Radioactive Isotopes, Solubility
  
Electron Configuration
[Xe] 4f14 5d2 6s2
  
[Xe] 4f14 5d10 6s2 6p4
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Monoclinic (MON)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
MON-Crystal-Structure-of-Polonium.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
13.60 cm3/mol
  
38
22.23 cm3/mol
  
13
Adjacent Atomic Numbers
  
  
Valence Electron Potential
81.00 (-eV)
  
16
Not Available
  
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
13.31 g/cm3
  
26
9.20 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 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, Malleable
  
NA
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Nonmagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
331.00 nΩ·m
  
14
Electrical Conductivity
0.03 106/cm Ω
  
39
0.02 106/cm Ω
  
99+
Electron Affinity
0.00 kJ/mol
  
40
183.30 kJ/mol
  
3
Specific Heat
0.14 J/(kg K)
  
37
0.12 J/(kg K)
  
40
Molar Heat Capacity
25.73 J/mol·K
  
36
26.40 J/mol·K
  
28
Thermal Conductivity
23.00 W/m·K
  
99+
20.00 W/m·K
  
99+
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
5.90 µm/(m·K)
  
99+
23.50 µm/(m·K)
  
16
Enthalpy
  
  
Enthalpy of Vaporization
661.10 kJ/mol
  
5
60.30 kJ/mol
  
99+
Enthalpy of Fusion
25.10 kJ/mol
  
8
13.00 kJ/mol
  
26
Enthalpy of Atomization
703.00 kJ/mol
  
5
134.00 kJ/mol
  
99+
Standard Molar Entropy
43.60 J/mol.K
  
34
Not Available