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What is Thallium?

Thallium In Periodic Table

Thallium Symbol
Tl

Group Number
13
5
📊

Period Number
6
📊

Block
p block
📊

Element Family
Post-​Transition
📊

CAS Number of Thallium
7440280
52

Space Group Name
P63/mmc

Space Group Number
194.00
5
📊

Facts about Thallium

Interesting Facts
  • Compounds of Thallium metal are highly Toxic.
  • Thallium metal is being suspected as a human carcinogen.

Sources
Found As a By-product, Ores of metals, Ores of Minerals

History of Thallium

Who Discovered
William Crookes

Discovery
In 1861

Abundance of Thallium

Abundance In Universe
0.00 %
32
📊

Abundance In Sun
0.00 %
27
📊

Abundance In Meteorites
0.00 %
41
📊

Abundance In Earth's Crust
0.00 %
42
📊

Abundance In Oceans
0.00 %
34
📊

Abundance In Humans
Not Available

Uses of Thallium

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.

Industrial Uses
Chemical Industry

Medical Uses
Medical Research

Other Uses
Alloys

Biological Properties

Toxicity
Highly Toxic
📊

Present in Human Body
📊

In Blood
0.00 Blood/mg dm-3
34

In Bone
0.00 p.p.m.
33

Physical Properties of Thallium

Thallium Melting Point
303.50 °C
69
📊

Thallium Boiling Point
1,457.00 °C
60
📊

Appearance of Thallium

Physical State
Solid
📊

Color
Silvery White

Luster
NA

Hardness of Thallium

Mohs Hardness
1.20
20
📊

Brinell Hardness
26.50 MPa
50
📊

Vickers Hardness
Not Available

Speed of Sound
818.00 m/s
53
📊

Optical Properties

Refractive Index
Not Available

Reflectivity
Not Available

Allotropes

α Allotropes
Not Available

β Allotropes
Not Available

γ Allotropes
Not Available

Chemical Properties of Thallium

Chemical Formula
Tl

Isotopes of Thallium

Known Isotopes
32
7
📊

Electronegativity

Pauling Electronegativity
1.62
21
📊

Sanderson Electronegativity
2.25
5
📊

Allred Rochow Electronegativity
1.44
17
📊

Mulliken-Jaffe Electronegativity
1.96
6
📊

Allen Electronegativity
1.79
13
📊

Electropositivity

Pauling Electropositivity
2.38
33
📊

Ionization Energies

1st Energy Level
589.40 kJ/mol
58
📊

2nd Energy Level
1,971.00 kJ/mol
14
📊

3rd Energy Level
2,878.00 kJ/mol
32
📊

4th Energy Level
Not Available

5th Energy Level
Not Available

6th Energy Level
Not Available

7th Energy level
Not Available

8th Energy Level
Not Available

9th Energy Level
Not Available

10th Energy Level
Not Available

11th Energy Level
Not Available

12th Energy Level
Not Available

13th Energy Level
Not Available

14th Energy Level
Not Available

15th Energy Level
Not Available

16th Energy Level
Not Available

17th Energy Level
Not Available

18th Energy Level
Not Available

19th Energy Level
Not Available

20th Energy Level
Not Available

21st Energy Level
Not Available

22nd Energy Level
Not Available

23rd Energy Level
Not Available

24th Energy Level
Not Available

25th Energy Level
Not Available

26th Energy Level
Not Available

27th Energy Level
Not Available

28th Energy Level
Not Available

29th Energy Level
Not Available

30th Energy Level
Not Available

Electrochemical Equivalent
7.63 g/amp-hr
2
📊

Electron Work Function
3.84 eV
28
📊

Other Chemical Properties
Corrosion, Ionization, Radioactive Isotopes, Solubility

Atomic Properties of Thallium

Atomic Number of Thallium
81
35
📊

Thallium Electron Configuration
[Xe] 4f14 5d10 6s2 6p1

Crystal Structure
Hexagonal Close Packed (HCP)
📊

Crystal Lattice
BCC-Crystal-Structure-.jpg#100

Atom of Thallium

Number of Protons
81
35
📊

Number of Neutrons
123
21
📊

Number of Electrons
81
35
📊

Radius of an Atom

Atomic Radius
170.00 pm
22
📊

Covalent Radius
145.00 pm
39
📊

Van der Waals Radius
196.00 pm
30
📊

Atomic Weight
204.38 amu
31
📊

Atomic Volume
17.20 cm3/mol
31
📊

Adjacent Atomic Numbers

Previous Element

Next Element

Valence Electron Potential
9.60 (-eV)
64
📊

Lattice Constant
345.66 pm
45
📊

Lattice Angles
π/2, π/2, 2 π/3

Lattice C/A Ratio
1.60
6
📊

Mechanical Properties of Thallium

Thallium Density

Density At Room Temperature
11.85 g/cm3
31
📊

Density When Liquid (at m.p.)
11.22 g/cm3
13
📊

Tensile Strength
Not Available

Viscosity
Not Available

Vapor Pressure of Thallium

Vapor Pressure at 1000 K
16.90 (Pa)
5
📊

Vapor Pressure at 2000 K
Not Available

Elasticity properties

Shear Modulus
2.80 GPa
51
📊

Bulk Modulus
43.00 GPa
28
📊

Young's Modulus
8.00 GPa
54
📊

Poisson Ratio
0.45
2
📊

Other Mechanical Properties
Ductile, Sectile

Magnetic Properties of Thallium

Magnetic Characteristics of Thallium

Specific Gravity
11.85
22
📊

Magnetic Ordering
Diamagnetic
📊

Permeability
Not Available

Susceptibility
Not Available

Electrical Properties

Electrical Property
Conductor
📊

Resistivity
0.18 nΩ·m
70
📊

Electrical Conductivity
0.06 106/cm Ω
32
📊

Electron Affinity
19.20 kJ/mol
32
📊

Thermal Properties of Thallium

Specific Heat
0.13 J/(kg K)
39
📊

Molar Heat Capacity
26.32 J/mol·K
29
📊

Thermal Conductivity
46.10 W/m·K
33
📊

Critical Temperature
Not Available

Thermal Expansion
29.90 µm/(m·K)
12
📊

Enthalpy of Thallium

Enthalpy of Vaporization
162.10 kJ/mol
45
📊

Enthalpy of Fusion
4.27 kJ/mol
54
📊

Enthalpy of Atomization
179.90 kJ/mol
48
📊

Standard Molar Entropy
64.20 J/mol.K
19
📊