Cadmium vs Chromium
Periodic Table
Symbol
Cd
Cr
Group Number
12
6
6
12
Period Number
5
4
Block
d block
d block
Element Family
Transition Metal
Transition Metal
CAS Number
7440439
99+
7440473
39
Space Group Name
P63/mmc
Im_ 3m
Space Group Number
194.00
5
229.00
1
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.
- Chromium is highly reactive, hence it is not found free in nature.
- Ores of Chromites mineral are the major source of Chromium metal.
- Almost 90% leather tanning is done with the help of chromium.
Sources
Found As a By-product, Found in Minerals, Mining
Found in Minerals, Mining, Ores of metals, Ores of Minerals
History
Who Discovered
Karl Samuel Leberecht Hermann and Friedrich Stromeyer
Louis Nicolas Vauquelin
Discovery
In 1817
In Between 1797 - 1798
Abundance
Abundance In Universe
2 * 10-7 %
22
1.5 * 10-3 %
7
Abundance In Sun
~0.0000006 %
21
~0.002 %
7
Abundance In Meteorites
0.00 %
31
0.30 %
7
Abundance In Earth's Crust
0.00 %
99+
0.01 %
13
Abundance In Oceans
0.00 %
28
0.00 %
16
Abundance In Humans
0.00 %
11
0.00 %
16
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.
- It is used to harden the steel and produces a stainless steel and other various alloys.
- It is also used to give proper finish to polished mirrors. Its chromium plates are used in bathroom fittings.
Industrial Uses
Aerospace Industry, Ammunition Industry, Chemical Industry, Electrical Industry, Electronic Industry
Automobile Industry, Chemical Industry
Medical Uses
NA
NA
Other Uses
Alloys
Alloys
Biological Properties
Toxicity
Toxic
Highly Toxic
Present in Human Body
Yes
Yes
In Blood
0.01 Blood/mg dm-3
24
0.11 Blood/mg dm-3
12
In Bone
1.80 p.p.m.
15
0.33 p.p.m.
21
Physical Properties
Melting Point
320.90 °C
99+
1,857.00 °C
14
Boiling Point
765.00 °C
99+
2,672.00 °C
39
Appearance
Physical State
Solid
Solid
Color
Silvery Bluish-Gray
Silver
Luster
Metallic
Metallic
Hardness
Mohs Hardness
2.00
16
8.50
1
Brinell Hardness
203.00 MPa
39
687.00 MPa
16
Vickers Hardness
Not Available
1,060.00 MPa
10
Speed of Sound
2,310.00 m/s
39
5,940.00 m/s
5
Optical Properties
Reflectivity
67.00 %
11
Not Available
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
Cr
Isotopes
Known Isotopes
34
5
21
18
Electronegativity
Pauling Electronegativity
1.69
17
1.66
18
Sanderson Electronegativity
1.98
9
1.66
14
Allred Rochow Electronegativity
1.46
15
1.56
10
Mulliken-Jaffe Electronegativity
1.53
13
Not Available
Allen Electronegativity
1.52
27
1.65
19
Electropositivity
Pauling Electropositivity
2.31
37
2.34
36
Ionization Energies
1st Energy Level
867.80 kJ/mol
11
26,130.00 kJ/mol
1
2nd Energy Level
1,631.40 kJ/mol
32
28,750.00 kJ/mol
1
3rd Energy Level
3,616.00 kJ/mol
13
34,230.00 kJ/mol
1
4th Energy Level
Not Available
37,066.00 kJ/mol
1
5th Energy Level
Not Available
97,510.00 kJ/mol
1
6th Energy Level
Not Available
105,800.00 kJ/mol
1
7th Energy level
Not Available
114,300.00 kJ/mol
1
8th Energy Level
Not Available
125,300.00 kJ/mol
1
9th Energy Level
Not Available
134,700.00 kJ/mol
1
10th Energy Level
Not Available
144,300.00 kJ/mol
1
11th Energy Level
Not Available
26,130.00 kJ/mol
12
12th Energy Level
Not Available
28,750.00 kJ/mol
13
13th Energy Level
Not Available
34,230.00 kJ/mol
10
14th Energy Level
Not Available
37,066.00 kJ/mol
12
15th Energy Level
Not Available
97,510.00 kJ/mol
1
16th Energy Level
Not Available
105,800.00 kJ/mol
2
17th Energy Level
Not Available
114,300.00 kJ/mol
3
18th Energy Level
Not Available
125,300.00 kJ/mol
4
19th Energy Level
Not Available
134,700.00 kJ/mol
5
20th Energy Level
Not Available
144,300.00 kJ/mol
7
21st Energy Level
Not Available
157,700.00 kJ/mol
7
22nd Energy Level
Not Available
166,090.00 kJ/mol
6
Electrochemical Equivalent
2.10 g/amp-hr
27
0.32 g/amp-hr
99+
Electron Work Function
4.22 eV
22
4.50 eV
14
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Chemical Stability, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
48
99+
24
99+
Electron Configuration
[Kr] 4d10 5s2
[Ar] 3d5 4s1
Crystal Structure
Hexagonal Close Packed (HCP)
Body Centered Cubic (BCC)
Crystal Lattice
HCP-Crystal-Structure-of-Cadmium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
48
99+
24
99+
Number of Neutrons
64
99+
28
99+
Number of Electrons
48
99+
24
99+
Radius of an Atom
Atomic Radius
151.00 pm
32
128.00 pm
99+
Covalent Radius
144.00 pm
40
139.00 pm
99+
Van der Waals Radius
158.00 pm
99+
200.00 pm
28
Atomic Weight
112.41 amu
99+
52.00 amu
99+
Atomic Volume
13.10 cm3/mol
39
7.23 cm3/mol
99+
Adjacent Atomic Numbers
Valence Electron Potential
30.00 (-eV)
99+
170.00 (-eV)
4
Lattice Constant
297.94 pm
99+
291.00 pm
99+
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+
7.19 g/cm3
99+
Density When Liquid (at m.p.)
8.00 g/cm3
28
6.30 g/cm3
40
Tensile Strength
62.00 MPa
16
689.00 MPa
7
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
0.00 (Pa)
24
Vapor Pressure at 2000 K
Not Available
774.00 (Pa)
1
Elasticity properties
Shear Modulus
19.00 GPa
35
115.00 GPa
9
Bulk Modulus
42.00 GPa
29
160.00 GPa
11
Young's Modulus
50.00 GPa
36
279.00 GPa
8
Poisson Ratio
0.30
14
0.21
32
Other Mechanical Properties
Ductile, Malleable
NA
Magnetic Properties
Magnetic Characteristics
Specific Gravity
8.65
36
7.19
99+
Magnetic Ordering
Diamagnetic
Antiferromagnetic
Electrical Properties
Electrical Property
Semiconductor
NA
Resistivity
72.70 nΩ·m
36
125.00 nΩ·m
27
Electrical Conductivity
0.14 106/cm Ω
15
0.08 106/cm Ω
25
Electron Affinity
0.00 kJ/mol
40
64.30 kJ/mol
15
Thermal Properties
Specific Heat
0.23 J/(kg K)
26
0.45 J/(kg K)
12
Molar Heat Capacity
26.02 J/mol·K
32
23.35 J/mol·K
99+
Thermal Conductivity
96.60 W/m·K
16
93.90 W/m·K
17
Critical Temperature
Not Available
Not Available
Thermal Expansion
30.80 µm/(m·K)
10
4.90 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
100.00 kJ/mol
99+
348.80 kJ/mol
24
Enthalpy of Fusion
6.19 kJ/mol
99+
15.31 kJ/mol
20
Enthalpy of Atomization
113.00 kJ/mol
99+
397.50 kJ/mol
21
Standard Molar Entropy
51.80 J/mol.K
27
23.80 J/mol.K
99+
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