Rhodium vs Polonium
Periodic Table
Symbol
Rh
Po
Group Number
9
9
16
2
Period Number
5
6
Block
d block
p block
Element Family
Transition Metal
Post-Transition
CAS Number
7440166
99+
7440086
99+
Space Group Name
Fm_ 3m
Pm-3m
Space Group Number
225.00
2
221.00
3
Facts
Interesting Facts
- Rhodium is the rarest element out of all non-radioactive metals on the earth .
- Rhodium is one of the most durable and hard metal, which also have high reflectance.
- 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
Earth's crust, Found As a By-product, Found in Minerals, Mining
Mining, Ores of metals
History
Who Discovered
William Hyde Wollaston
Pierre Curie and Marie Curie
Discovery
In 1804
In 1898
Abundance
Abundance In Universe
6 * 10-8 %
26
Not Available
Abundance In Sun
~0.0000002 %
25
~-9999 %
Abundance In Meteorites
0.00 %
36
Not Available
Abundance In Earth's Crust
0.00 %
99+
Not Available
Abundance In Oceans
Not Available
0.00 %
99+
Uses
Uses & Benefits
- Rhodium metal is mainly used in catalytic converters for cars as it reduces nitrogen oxides in exhaust gases.
- It is used as an industrial catalyst for nitric acid, acetic acid, hydrogenation reaction, etc.
- 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
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Aerospace Industry, Ammunition Industry
Medical Uses
NA
NA
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
NA
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
1,966.00 °C
12
254.00 °C
99+
Boiling Point
3,727.00 °C
17
962.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Silvery White
Silver
Luster
Metallic
NA
Hardness
Mohs Hardness
6.00
6
Not Available
Brinell Hardness
980.00 MPa
9
Not Available
Vickers Hardness
1,100.00 MPa
9
Not Available
Speed of Sound
4,700.00 m/s
15
Not Available
Optical Properties
Reflectivity
84.00 %
4
Not Available
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
Rh
Po
Isotopes
Known Isotopes
16
23
29
10
Electronegativity
Pauling Electronegativity
2.28
3
2.00
7
Allred Rochow Electronegativity
1.45
16
1.76
2
Mulliken-Jaffe Electronegativity
Not Available
2.48
1
Allen Electronegativity
1.56
24
2.19
2
Electropositivity
Pauling Electropositivity
1.72
99+
2.00
99+
Ionization Energies
1st Energy Level
719.70 kJ/mol
29
812.10 kJ/mol
14
2nd Energy Level
1,740.00 kJ/mol
26
Not Available
3rd Energy Level
2,997.00 kJ/mol
27
Not Available
Electrochemical Equivalent
1.28 g/amp-hr
99+
3.90 g/amp-hr
8
Electron Work Function
4.98 eV
6
Not Available
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes
Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
45
99+
84
32
Electron Configuration
[Kr] 4d8 5s1
[Xe] 4f14 5d10 6s2 6p4
Crystal Structure
Face Centered Cubic (FCC)
Monoclinic (MON)
Crystal Lattice
FCC-Crystal-Structure-of-Rhodium.jpg#100
MON-Crystal-Structure-of-Polonium.jpg#100
Atom
Number of Protons
45
99+
84
32
Number of Neutrons
58
99+
125
19
Number of Electrons
45
99+
84
32
Radius of an Atom
Atomic Radius
134.00 pm
99+
168.00 pm
23
Covalent Radius
142.00 pm
99+
140.00 pm
99+
Van der Waals Radius
200.00 pm
28
197.00 pm
29
Atomic Weight
102.91 amu
99+
209.00 amu
28
Atomic Volume
8.30 cm3/mol
99+
22.23 cm3/mol
13
Adjacent Atomic Numbers
Valence Electron Potential
64.00 (-eV)
22
Not Available
Lattice Constant
380.34 pm
27
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
12.41 g/cm3
28
9.20 g/cm3
99+
Density When Liquid (at m.p.)
10.70 g/cm3
14
9.40 g/cm3
19
Tensile Strength
951.00 MPa
5
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
0.02 (Pa)
19
Not Available
Elasticity properties
Shear Modulus
150.00 GPa
6
Not Available
Bulk Modulus
275.00 GPa
5
Not Available
Young's Modulus
380.00 GPa
5
Not Available
Poisson Ratio
0.26
22
Not Available
Other Mechanical Properties
Malleable
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
12.41
20
9.32
31
Magnetic Ordering
Paramagnetic
Nonmagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
43.30 nΩ·m
99+
0.40 nΩ·m
99+
Electrical Conductivity
0.21 106/cm Ω
8
0.02 106/cm Ω
99+
Electron Affinity
109.70 kJ/mol
7
183.30 kJ/mol
3
Thermal Properties
Specific Heat
0.24 J/(kg K)
22
0.12 J/(kg K)
40
Molar Heat Capacity
24.98 J/mol·K
99+
26.40 J/mol·K
28
Thermal Conductivity
150.00 W/m·K
9
20.00 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
8.20 µm/(m·K)
99+
23.50 µm/(m·K)
16
Enthalpy
Enthalpy of Vaporization
495.40 kJ/mol
12
60.30 kJ/mol
99+
Enthalpy of Fusion
21.76 kJ/mol
10
13.00 kJ/mol
26
Enthalpy of Atomization
556.50 kJ/mol
12
134.00 kJ/mol
99+
Standard Molar Entropy
31.50 J/mol.K
99+
Not Available
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