Protactinium Polonium Comparison
Periodic Table
Symbol
Pa
Po
Group Number
Not Available
16
2
Period Number
7
6
Block
f block
p block
Element Family
Actinide
Post-Transition
CAS Number
7440133
99+
7440086
99+
Space Group Name
I4/mmm
Pm-3m
Space Group Number
139.00
8
221.00
3
Facts
Interesting Facts
- Protactinium metal has 29 isotopes.
- Isotopes of Protactinium-231 used in nuclear weapon.
- 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
Found in Uranium Ores, Mining, Ores of metals
Mining, Ores of metals
History
Who Discovered
William Crookes
Pierre Curie and Marie Curie
Discovery
In 1900
In 1898
Abundance
Abundance In Earth's Crust
0.00 %
99+
Not Available
Abundance In Oceans
0.00 %
99+
0.00 %
99+
Uses
Uses & Benefits
- Currently known uses of Protactinium metal are limited to research purpose only.
- 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
NA
Aerospace Industry, Ammunition Industry
Medical Uses
NA
NA
Other Uses
NA
Alloys
Biological Properties
Toxicity
Highly Toxic
Highly Toxic
Present in Human Body
No
No
In Blood
0.00 Blood/mg dm-3
37
0.00 Blood/mg dm-3
37
In Bone
0.00 p.p.m.
36
0.00 p.p.m.
36
Physical Properties
Melting Point
1,568.00 °C
21
254.00 °C
99+
Boiling Point
4,027.00 °C
12
962.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Silver
Silver
Luster
Metallic
NA
Hardness
Speed of Sound
Not Available
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
Pa
Po
Isotopes
Known Isotopes
27
12
29
10
Electronegativity
Pauling Electronegativity
1.50
27
2.00
7
Allred Rochow Electronegativity
1.14
28
1.76
2
Mulliken-Jaffe Electronegativity
Not Available
2.48
1
Allen Electronegativity
Not Available
2.19
2
Electropositivity
Pauling Electropositivity
2.50
27
2.00
99+
Ionization Energies
1st Energy Level
568.00 kJ/mol
99+
812.10 kJ/mol
14
2nd Energy Level
1,128.00 kJ/mol
99+
Not Available
3rd Energy Level
1,814.00 kJ/mol
99+
Not Available
4th Energy Level
2,991.00 kJ/mol
99+
Not Available
Electrochemical Equivalent
1.72 g/amp-hr
99+
3.90 g/amp-hr
8
Electron Work Function
Not Available
Not Available
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity
Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
91
27
84
32
Electron Configuration
[Rn] 5f2 6d1 7s2
[Xe] 4f14 5d10 6s2 6p4
Crystal Structure
Tetragonal (TETR)
Monoclinic (MON)
Crystal Lattice
TETR-Crystal-Structure-of-Protactinium.jpg#100
MON-Crystal-Structure-of-Polonium.jpg#100
Atom
Number of Protons
91
27
84
32
Number of Neutrons
122
21
125
19
Number of Electrons
91
27
84
32
Radius of an Atom
Atomic Radius
163.00 pm
25
168.00 pm
23
Covalent Radius
200.00 pm
11
140.00 pm
99+
Van der Waals Radius
243.00 pm
11
197.00 pm
29
Atomic Weight
231.04 amu
24
209.00 amu
28
Atomic Volume
15.00 cm3/mol
34
22.23 cm3/mol
13
Adjacent Atomic Numbers
Valence Electron Potential
92.00 (-eV)
11
Not Available
Lattice Constant
392.50 pm
23
335.90 pm
99+
Lattice Angles
π/2, π/2, π/2
π/2, π/2, π/2
Lattice C/A Ratio
Not Available
Not Available
Mechanical Properties
Density
Density At Room Temperature
15.37 g/cm3
20
9.20 g/cm3
99+
Density When Liquid (at m.p.)
Not Available
9.40 g/cm3
19
Tensile Strength
Not Available
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Elasticity properties
Poisson Ratio
Not Available
Not Available
Other Mechanical Properties
Unknown
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
15.37
12
9.32
31
Magnetic Ordering
Paramagnetic
Nonmagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
177.00 nΩ·m
21
0.40 nΩ·m
99+
Electrical Conductivity
0.05 106/cm Ω
34
0.02 106/cm Ω
99+
Electron Affinity
Not Available
183.30 kJ/mol
3
Thermal Properties
Specific Heat
0.12 J/(kg K)
40
0.12 J/(kg K)
40
Molar Heat Capacity
Not Available
26.40 J/mol·K
28
Thermal Conductivity
47.00 W/m·K
32
20.00 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
9.90 µm/(m·K)
40
23.50 µm/(m·K)
16
Enthalpy
Enthalpy of Vaporization
Not Available
60.30 kJ/mol
99+
Enthalpy of Fusion
12.34 kJ/mol
28
13.00 kJ/mol
26
Enthalpy of Atomization
Not Available
134.00 kJ/mol
99+
Standard Molar Entropy
198.10 J/mol.K
1
Not Available
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