Cadmium Rhodium Comparison
Periodic Table
Symbol
Cd
Rh
Group Number
12
6
9
9
Period Number
5
5
Block
d block
d block
Element Family
Transition Metal
Transition Metal
CAS Number
7440439
99+
7440166
99+
Space Group Name
P63/mmc
Fm_ 3m
Space Group Number
194.00
5
225.00
2
Facts
Interesting Facts
- Naturally occurring minor elements include Cadmium.
- Cadmium is released into atmosphere to control volcanic eruption and forest fires.
- It is used for electroplating of Steel for corrosion resistance.
- It can absorb neutrons and used in nuclear reactor to control atomic fission.
- 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 As a By-product, Found in Minerals, Mining
Earth's crust, Found As a By-product, Found in Minerals, Mining
History
Who Discovered
Karl Samuel Leberecht Hermann and Friedrich Stromeyer
William Hyde Wollaston
Discovery
In 1817
In 1804
Abundance
Abundance In Universe
2 * 10-7 %
22
6 * 10-8 %
26
Abundance In Sun
~0.0000006 %
21
~0.0000002 %
25
Abundance In Meteorites
0.00 %
31
0.00 %
36
Abundance In Earth's Crust
0.00 %
99+
0.00 %
99+
Abundance In Oceans
0.00 %
28
Not Available
Abundance In Humans
0.00 %
11
Not Available
Uses
Uses & Benefits
- It has very limited uses as it is a toxic metal and it can cause birth defects, cancer, etc.
- Almost 80% of Cadmium metal is used in Nickel cadmium Batteries and now it is getting replaced with nickel hydride.
- 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, Ammunition 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
Toxic
NA
Present in Human Body
Yes
No
In Blood
0.01 Blood/mg dm-3
24
Not Available
In Bone
1.80 p.p.m.
15
Not Available
Physical Properties
Melting Point
320.90 °C
99+
1,966.00 °C
12
Boiling Point
765.00 °C
99+
3,727.00 °C
17
Appearance
Physical State
Solid
Solid
Color
Silvery Bluish-Gray
Silvery White
Luster
Metallic
Metallic
Hardness
Mohs Hardness
2.00
16
6.00
6
Brinell Hardness
203.00 MPa
39
980.00 MPa
9
Vickers Hardness
Not Available
1,100.00 MPa
9
Speed of Sound
2,310.00 m/s
39
4,700.00 m/s
15
Optical Properties
Reflectivity
67.00 %
11
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
Cd
Rh
Isotopes
Known Isotopes
34
5
16
23
Electronegativity
Pauling Electronegativity
1.69
17
2.28
3
Sanderson Electronegativity
1.98
9
Not Available
Allred Rochow Electronegativity
1.46
15
1.45
16
Mulliken-Jaffe Electronegativity
1.53
13
Not Available
Allen Electronegativity
1.52
27
1.56
24
Electropositivity
Pauling Electropositivity
2.31
37
1.72
99+
Ionization Energies
1st Energy Level
867.80 kJ/mol
11
719.70 kJ/mol
29
2nd Energy Level
1,631.40 kJ/mol
32
1,740.00 kJ/mol
26
3rd Energy Level
3,616.00 kJ/mol
13
2,997.00 kJ/mol
27
Electrochemical Equivalent
2.10 g/amp-hr
27
1.28 g/amp-hr
99+
Electron Work Function
4.22 eV
22
4.98 eV
6
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Ionization, Radioactive Isotopes
Atomic Properties
Atomic Number
48
99+
45
99+
Electron Configuration
[Kr] 4d10 5s2
[Kr] 4d8 5s1
Crystal Structure
Hexagonal Close Packed (HCP)
Face Centered Cubic (FCC)
Crystal Lattice
HCP-Crystal-Structure-of-Cadmium.jpg#100
FCC-Crystal-Structure-of-Rhodium.jpg#100
Atom
Number of Protons
48
99+
45
99+
Number of Neutrons
64
99+
58
99+
Number of Electrons
48
99+
45
99+
Radius of an Atom
Atomic Radius
151.00 pm
32
134.00 pm
99+
Covalent Radius
144.00 pm
40
142.00 pm
99+
Van der Waals Radius
158.00 pm
99+
200.00 pm
28
Atomic Weight
112.41 amu
99+
102.91 amu
99+
Atomic Volume
13.10 cm3/mol
39
8.30 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
30.00 (-eV)
99+
64.00 (-eV)
22
Lattice Constant
297.94 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
1.89
1
Not Available
Mechanical Properties
Density
Density At Room Temperature
8.65 g/cm3
99+
12.41 g/cm3
28
Density When Liquid (at m.p.)
8.00 g/cm3
28
10.70 g/cm3
14
Tensile Strength
62.00 MPa
16
951.00 MPa
5
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
Not Available
0.02 (Pa)
19
Elasticity properties
Shear Modulus
19.00 GPa
35
150.00 GPa
6
Bulk Modulus
42.00 GPa
29
275.00 GPa
5
Young's Modulus
50.00 GPa
36
380.00 GPa
5
Poisson Ratio
0.30
14
0.26
22
Other Mechanical Properties
Ductile, Malleable
Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
8.65
36
12.41
20
Magnetic Ordering
Diamagnetic
Paramagnetic
Electrical Properties
Electrical Property
Semiconductor
Conductor
Resistivity
72.70 nΩ·m
36
43.30 nΩ·m
99+
Electrical Conductivity
0.14 106/cm Ω
15
0.21 106/cm Ω
8
Electron Affinity
0.00 kJ/mol
40
109.70 kJ/mol
7
Thermal Properties
Specific Heat
0.23 J/(kg K)
26
0.24 J/(kg K)
22
Molar Heat Capacity
26.02 J/mol·K
32
24.98 J/mol·K
99+
Thermal Conductivity
96.60 W/m·K
16
150.00 W/m·K
9
Critical Temperature
Not Available
Not Available
Thermal Expansion
30.80 µm/(m·K)
10
8.20 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
100.00 kJ/mol
99+
495.40 kJ/mol
12
Enthalpy of Fusion
6.19 kJ/mol
99+
21.76 kJ/mol
10
Enthalpy of Atomization
113.00 kJ/mol
99+
556.50 kJ/mol
12
Standard Molar Entropy
51.80 J/mol.K
27
31.50 J/mol.K
99+
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