Cadmium vs Thallium
Periodic Table
Symbol
Cd
Tl
Group Number
12
6
13
5
Period Number
5
6
Block
d block
p block
Element Family
Transition Metal
Post-Transition
CAS Number
7440439
99+
7440280
99+
Space Group Name
P63/mmc
P63/mmc
Space Group Number
194.00
5
194.00
5
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.
- Compounds of Thallium metal are highly Toxic.
- Thallium metal is being suspected as a human carcinogen.
Sources
Found As a By-product, Found in Minerals, Mining
Found As a By-product, Ores of metals, Ores of Minerals
History
Who Discovered
Karl Samuel Leberecht Hermann and Friedrich Stromeyer
William Crookes
Discovery
In 1817
In 1861
Abundance
Abundance In Universe
2 * 10-7 %
22
5 * 10-9 %
32
Abundance In Sun
~0.0000006 %
21
~0.0000001 %
26
Abundance In Meteorites
0.00 %
31
0.00 %
99+
Abundance In Earth's Crust
0.00 %
99+
0.00 %
99+
Abundance In Oceans
0.00 %
28
0.00 %
34
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.
- Thallium is a toxic metal and hence it has limited uses. Thallium metal is mostly used for producing photoelectric cells.
- In thermometer’s mercury alloy has 8% of thallium, as it has a melting point lower than 20°C.
Industrial Uses
Aerospace Industry, Ammunition Industry, Chemical Industry, Electrical Industry, Electronic Industry
Chemical Industry
Medical Uses
NA
Medical Research
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
0.00 Blood/mg dm-3
34
In Bone
1.80 p.p.m.
15
0.00 p.p.m.
33
Physical Properties
Melting Point
320.90 °C
99+
303.50 °C
99+
Boiling Point
765.00 °C
99+
1,457.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Silvery Bluish-Gray
Silvery White
Luster
Metallic
NA
Hardness
Mohs Hardness
2.00
16
1.20
20
Brinell Hardness
203.00 MPa
39
26.50 MPa
99+
Speed of Sound
2,310.00 m/s
39
818.00 m/s
99+
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
Tl
Isotopes
Known Isotopes
34
5
32
7
Electronegativity
Pauling Electronegativity
1.69
17
1.62
21
Sanderson Electronegativity
1.98
9
2.25
5
Allred Rochow Electronegativity
1.46
15
1.44
17
Mulliken-Jaffe Electronegativity
1.53
13
1.96
6
Allen Electronegativity
1.52
27
1.79
13
Electropositivity
Pauling Electropositivity
2.31
37
2.38
33
Ionization Energies
1st Energy Level
867.80 kJ/mol
11
589.40 kJ/mol
99+
2nd Energy Level
1,631.40 kJ/mol
32
1,971.00 kJ/mol
14
3rd Energy Level
3,616.00 kJ/mol
13
2,878.00 kJ/mol
32
Electrochemical Equivalent
2.10 g/amp-hr
27
7.63 g/amp-hr
2
Electron Work Function
4.22 eV
22
3.84 eV
28
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
48
99+
81
35
Electron Configuration
[Kr] 4d10 5s2
[Xe] 4f14 5d10 6s2 6p1
Crystal Structure
Hexagonal Close Packed (HCP)
Hexagonal Close Packed (HCP)
Crystal Lattice
HCP-Crystal-Structure-of-Cadmium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
48
99+
81
35
Number of Neutrons
64
99+
123
20
Number of Electrons
48
99+
81
35
Radius of an Atom
Atomic Radius
151.00 pm
32
170.00 pm
22
Covalent Radius
144.00 pm
40
145.00 pm
39
Van der Waals Radius
158.00 pm
99+
196.00 pm
30
Atomic Weight
112.41 amu
99+
204.38 amu
31
Atomic Volume
13.10 cm3/mol
39
17.20 cm3/mol
31
Adjacent Atomic Numbers
Valence Electron Potential
30.00 (-eV)
99+
9.60 (-eV)
99+
Lattice Constant
297.94 pm
99+
345.66 pm
99+
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, 2 π/3
Lattice C/A Ratio
1.89
1
1.60
6
Mechanical Properties
Density
Density At Room Temperature
8.65 g/cm3
99+
11.85 g/cm3
31
Density When Liquid (at m.p.)
8.00 g/cm3
28
11.22 g/cm3
13
Tensile Strength
62.00 MPa
16
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
16.90 (Pa)
5
Elasticity properties
Shear Modulus
19.00 GPa
35
2.80 GPa
99+
Bulk Modulus
42.00 GPa
29
43.00 GPa
28
Young's Modulus
50.00 GPa
36
8.00 GPa
99+
Poisson Ratio
0.30
14
0.45
2
Other Mechanical Properties
Ductile, Malleable
Ductile, Sectile
Magnetic Properties
Magnetic Characteristics
Specific Gravity
8.65
36
11.85
22
Magnetic Ordering
Diamagnetic
Diamagnetic
Electrical Properties
Electrical Property
Semiconductor
Conductor
Resistivity
72.70 nΩ·m
36
0.18 nΩ·m
99+
Electrical Conductivity
0.14 106/cm Ω
15
0.06 106/cm Ω
32
Electron Affinity
0.00 kJ/mol
40
19.20 kJ/mol
32
Thermal Properties
Specific Heat
0.23 J/(kg K)
26
0.13 J/(kg K)
39
Molar Heat Capacity
26.02 J/mol·K
32
26.32 J/mol·K
29
Thermal Conductivity
96.60 W/m·K
16
46.10 W/m·K
33
Critical Temperature
Not Available
Not Available
Thermal Expansion
30.80 µm/(m·K)
10
29.90 µm/(m·K)
12
Enthalpy
Enthalpy of Vaporization
100.00 kJ/mol
99+
162.10 kJ/mol
99+
Enthalpy of Fusion
6.19 kJ/mol
99+
4.27 kJ/mol
99+
Enthalpy of Atomization
113.00 kJ/mol
99+
179.90 kJ/mol
99+
Standard Molar Entropy
51.80 J/mol.K
27
64.20 J/mol.K
19
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