Rhenium vs Rhodium
Periodic Table
Symbol
Re
Rh
Group Number
7
11
9
9
Period Number
6
5
Block
d block
d block
Element Family
Transition Metal
Transition Metal
CAS Number
7440155
99+
7440166
99+
Space Group Name
P63/mmc
Fm_ 3m
Space Group Number
194.00
5
225.00
2
Facts
Interesting Facts
- Chemical properties of Rhenium are similar to Manganese.
- Rhenium metal is created while refining Molybdenum.
- 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.
Sources
Found in Minerals, Mining, Ores of Minerals
Earth's crust, Found As a By-product, Found in Minerals, Mining
History
Who Discovered
Masataka Ogawa
William Hyde Wollaston
Discovery
In 1908
In 1804
Abundance
Abundance In Universe
2 * 10-8 %
29
6 * 10-8 %
26
Abundance In Sun
~0.00000001 %
29
~0.0000002 %
25
Abundance In Meteorites
0.00 %
99+
0.00 %
36
Abundance In Earth's Crust
0.00 %
99+
0.00 %
99+
Abundance In Oceans
0.00 %
34
Not Available
Uses
Uses & Benefits
- 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.
- 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.
Industrial Uses
Aerospace Industry, Automobile Industry, Chemical Industry, Electrical Industry, Electronic Industry
Aerospace Industry, Automobile Industry, Electrical Industry, Electronic Industry
Medical Uses
NA
NA
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Low Toxic
NA
Present in Human Body
No
No
Physical Properties
Melting Point
3,180.00 °C
2
1,966.00 °C
12
Boiling Point
5,627.00 °C
2
3,727.00 °C
17
Appearance
Physical State
Solid
Solid
Color
Silvery Gray
Silvery White
Luster
Metallic
Metallic
Hardness
Mohs Hardness
7.00
3
6.00
6
Brinell Hardness
1,320.00 MPa
8
980.00 MPa
9
Vickers Hardness
1,350.00 MPa
7
1,100.00 MPa
9
Speed of Sound
4,700.00 m/s
15
4,700.00 m/s
15
Optical Properties
Reflectivity
Not Available
84.00 %
4
Allotropes
No
No
α Allotropes
Not Available
Not Available
β Allotropes
Not Available
Not Available
γ Allotropes
Not Available
Not Available
Chemical Properties
Chemical Formula
Re
Rh
Isotopes
Known Isotopes
33
6
16
23
Electronegativity
Pauling Electronegativity
1.90
11
2.28
3
Allred Rochow Electronegativity
1.46
15
1.45
16
Allen Electronegativity
1.60
21
1.56
24
Electropositivity
Pauling Electropositivity
2.10
99+
1.72
99+
Ionization Energies
1st Energy Level
760.00 kJ/mol
20
719.70 kJ/mol
29
2nd Energy Level
1,260.00 kJ/mol
99+
1,740.00 kJ/mol
26
3rd Energy Level
2,510.00 kJ/mol
99+
2,997.00 kJ/mol
27
4th Energy Level
3,640.00 kJ/mol
99+
Not Available
Electrochemical Equivalent
0.99 g/amp-hr
99+
1.28 g/amp-hr
99+
Electron Work Function
4.96 eV
7
4.98 eV
6
Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Ionization, Radioactive Isotopes
Atomic Properties
Atomic Number
75
99+
45
99+
Electron Configuration
[Xe] 4f14 5d5 6s2
[Kr] 4d8 5s1
Crystal Structure
Hexagonal Close Packed (HCP)
Face Centered Cubic (FCC)
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
FCC-Crystal-Structure-of-Rhodium.jpg#100
Atom
Number of Protons
75
40
45
99+
Number of Neutrons
111
26
58
99+
Number of Electrons
75
40
45
99+
Radius of an Atom
Atomic Radius
137.00 pm
40
134.00 pm
99+
Covalent Radius
151.00 pm
34
142.00 pm
99+
Van der Waals Radius
200.00 pm
28
200.00 pm
28
Atomic Weight
186.21 amu
36
102.91 amu
99+
Atomic Volume
8.85 cm3/mol
99+
8.30 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
180.00 (-eV)
3
64.00 (-eV)
22
Lattice Constant
276.10 pm
99+
380.34 pm
27
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, π/2
Lattice C/A Ratio
1.62
3
Not Available
Mechanical Properties
Density
Density At Room Temperature
21.02 g/cm3
12
12.41 g/cm3
28
Density When Liquid (at m.p.)
18.90 g/cm3
4
10.70 g/cm3
14
Tensile Strength
1,070.00 MPa
3
951.00 MPa
5
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
0.00 (Pa)
29
0.02 (Pa)
19
Elasticity properties
Shear Modulus
178.00 GPa
3
150.00 GPa
6
Bulk Modulus
370.00 GPa
2
275.00 GPa
5
Young's Modulus
463.00 GPa
2
380.00 GPa
5
Poisson Ratio
0.30
14
0.26
22
Other Mechanical Properties
Ductile, Malleable
Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
21.02
5
12.41
20
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
193.00 nΩ·m
20
43.30 nΩ·m
99+
Electrical Conductivity
0.05 106/cm Ω
33
0.21 106/cm Ω
8
Electron Affinity
14.50 kJ/mol
35
109.70 kJ/mol
7
Thermal Properties
Specific Heat
0.13 J/(kg K)
39
0.24 J/(kg K)
22
Molar Heat Capacity
25.48 J/mol·K
38
24.98 J/mol·K
99+
Thermal Conductivity
48.00 W/m·K
31
150.00 W/m·K
9
Critical Temperature
Not Available
Not Available
Thermal Expansion
6.20 µm/(m·K)
99+
8.20 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
707.10 kJ/mol
3
495.40 kJ/mol
12
Enthalpy of Fusion
33.05 kJ/mol
2
21.76 kJ/mol
10
Enthalpy of Atomization
791.00 kJ/mol
2
556.50 kJ/mol
12
Standard Molar Entropy
36.90 J/mol.K
99+
31.50 J/mol.K
99+
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