Symbol
Tl
  
Pb
  
Period Number
6
  
6
  
Block
p block
  
p block
  
Element Family
Post-Transition
  
Post-Transition
  
Space Group Name
P63/mmc
  
Fm_ 3m
  
Interesting Facts
- Compounds of Thallium metal are highly Toxic.
- Thallium metal is being suspected as a human carcinogen.
  
- Galena mineral contains almost 87% of Lead metal in it, Galena is sulfide mineral.
- The best available source of Lead metal today is by recycling automobile batteries.
  
Sources
Found As a By-product, Ores of metals, Ores of Minerals
  
Earth's crust, Found in Minerals, Mining, Ores of metals, Ores of Minerals
  
History
  
  
Who Discovered
William Crookes
  
Unknown
  
Discovery
In 1861
  
In Middle Easterns (7000 BCE)
  
Abundance
  
  
Abundance In Sun
~0.0000001 %
  
26
~0.000001 %
  
18
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
Uses & Benefits
- 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.
  
- It is also used in insecticides, hair dyes and as an anti-knocking additive for petrol. But all these are banned by the government as Lead metal is known for detrimental to health.
  
Industrial Uses
Chemical Industry
  
Chemical Industry, Electrical Industry, Electronic Industry
  
Medical Uses
Medical Research
  
Surgical Instruments Manufacturing
  
Other Uses
Alloys
  
Alloys
  
Biological Properties
  
  
Toxicity
Highly Toxic
  
Toxic
  
Present in Human Body
Yes
  
Yes
  
In Blood
0.00 Blood/mg dm-3
  
34
0.21 Blood/mg dm-3
  
11
In Bone
0.00 p.p.m.
  
33
30.00 p.p.m.
  
10
Boiling Point
1,457.00 °C
  
99+
1,740.00 °C
  
99+
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Silvery White
  
Gray
  
Luster
NA
  
Metallic
  
Hardness
  
  
Speed of Sound
818.00 m/s
  
99+
1,190.00 m/s
  
99+
Optical Properties
  
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Tl
  
Pb
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Sanderson Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
589.40 kJ/mol
  
99+
715.60 kJ/mol
  
31
2nd Energy Level
1,971.00 kJ/mol
  
14
1,450.50 kJ/mol
  
99+
3rd Energy Level
2,878.00 kJ/mol
  
32
3,081.50 kJ/mol
  
23
4th Energy Level
Not Available
  
4,083.00 kJ/mol
  
35
5th Energy Level
Not Available
  
6,640.00 kJ/mol
  
20
Electrochemical Equivalent
7.63 g/amp-hr
  
2
3.87 g/amp-hr
  
9
Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Anti Corrosion, Ionization, Radioactive Isotopes
  
Electron Configuration
[Xe] 4f14 5d10 6s2 6p1
  
[Xe] 4f14 5d10 6s2 6p2
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Face Centered Cubic (FCC)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
FCC-Crystal-Structure-of-Lead.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
17.20 cm3/mol
  
31
18.17 cm3/mol
  
27
Adjacent Atomic Numbers
  
  
Valence Electron Potential
9.60 (-eV)
  
99+
24.20 (-eV)
  
99+
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Lattice C/A Ratio
Not Available
  
Density
  
  
Density At Room Temperature
11.85 g/cm3
  
31
11.34 g/cm3
  
33
Density When Liquid (at m.p.)
11.22 g/cm3
  
13
10.66 g/cm3
  
15
Tensile Strength
Not Available
  
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Sectile
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Diamagnetic
  
Diamagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Poor Conductor
  
Resistivity
208.00 nΩ·m
  
16
Electrical Conductivity
0.06 106/cm Ω
  
32
0.05 106/cm Ω
  
36
Electron Affinity
19.20 kJ/mol
  
32
35.10 kJ/mol
  
28
Specific Heat
0.13 J/(kg K)
  
39
0.13 J/(kg K)
  
39
Molar Heat Capacity
26.32 J/mol·K
  
29
26.65 J/mol·K
  
26
Thermal Conductivity
46.10 W/m·K
  
33
35.30 W/m·K
  
38
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
29.90 µm/(m·K)
  
12
28.90 µm/(m·K)
  
13
Enthalpy
  
  
Enthalpy of Vaporization
162.10 kJ/mol
  
99+
179.40 kJ/mol
  
99+
Enthalpy of Fusion
4.27 kJ/mol
  
99+
4.77 kJ/mol
  
99+
Enthalpy of Atomization
179.90 kJ/mol
  
99+
194.60 kJ/mol
  
99+
Standard Molar Entropy
64.20 J/mol.K
  
19
64.80 J/mol.K
  
17