Hafnium vs Polonium
Periodic Table
Symbol
Hf
Po
Group Number
4
14
16
2
Period Number
6
6
Block
d block
p block
Element Family
Transition Metal
Post-Transition
CAS Number
7440586
30
7440086
99+
Space Group Name
P63/mmc
Pm-3m
Space Group Number
194.00
5
221.00
3
Facts
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
7 * 10-8 %
25
Not Available
Abundance In Sun
~0.0000001 %
26
~-9999 %
Abundance In Meteorites
0.00 %
37
Not Available
Abundance In Earth's Crust
0.00 %
31
Not Available
Abundance In Oceans
0.00 %
27
0.00 %
99+
Uses
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
Physical Properties
Melting Point
2,150.00 °C
10
254.00 °C
99+
Boiling Point
5,400.00 °C
5
962.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Gray
Silver
Luster
Metallic
NA
Hardness
Mohs Hardness
5.50
7
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 Properties
Chemical Formula
Hf
Po
Isotopes
Known Isotopes
32
7
29
10
Electronegativity
Pauling Electronegativity
1.30
32
2.00
7
Allred Rochow Electronegativity
1.23
25
1.76
2
Mulliken-Jaffe Electronegativity
Not Available
2.48
1
Allen Electronegativity
1.16
37
2.19
2
Electropositivity
Pauling Electropositivity
2.70
22
2.00
99+
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
3.90 eV
27
Not Available
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
72
99+
84
32
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
Number of Protons
72
99+
84
32
Number of Neutrons
106
29
125
19
Number of Electrons
72
99+
84
32
Radius of an Atom
Atomic Radius
159.00 pm
28
168.00 pm
23
Covalent Radius
175.00 pm
23
140.00 pm
99+
Van der Waals Radius
200.00 pm
28
197.00 pm
29
Atomic Weight
178.49 amu
39
209.00 amu
28
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 Constant
319.64 pm
99+
335.90 pm
99+
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.58
12
Not Available
Mechanical Properties
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
9.40 g/cm3
19
Tensile Strength
445.00 MPa
8
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
0.00 (Pa)
24
Not Available
Elasticity properties
Shear Modulus
30.00 GPa
23
Not Available
Bulk Modulus
110.00 GPa
15
Not Available
Young's Modulus
78.00 GPa
25
Not Available
Poisson Ratio
0.37
7
Not Available
Other Mechanical Properties
Ductile, Malleable
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
13.31
18
9.32
31
Magnetic Ordering
Paramagnetic
Nonmagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
331.00 nΩ·m
14
0.40 nΩ·m
99+
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
Thermal Properties
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
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