Hafnium Thallium Comparison
Periodic Table
Symbol
Hf
Tl
Group Number
4
14
13
5
Period Number
6
6
Block
d block
p block
Element Family
Transition Metal
Post-Transition
CAS Number
7440586
30
7440280
99+
Space Group Name
P63/mmc
P63/mmc
Space Group Number
194.00
5
194.00
5
Facts
Interesting Facts
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
- Compounds of Thallium metal are highly Toxic.
- Thallium metal is being suspected as a human carcinogen.
Sources
By-product Zirconium Refining
Found As a By-product, Ores of metals, Ores of Minerals
History
Who Discovered
Dirk Coster and George de Hevesy
William Crookes
Discovery
In 1922
In 1861
Abundance
Abundance In Universe
7 * 10-8 %
25
5 * 10-9 %
32
Abundance In Sun
~0.0000001 %
26
~0.0000001 %
26
Abundance In Meteorites
0.00 %
37
0.00 %
99+
Abundance In Earth's Crust
0.00 %
31
0.00 %
99+
Abundance In Oceans
0.00 %
27
0.00 %
34
Uses
Uses & Benefits
- It has an ability to absorb neutrons and hence it is used to make control rods in nuclear submarines. And this metal is also used in Plasma welding torches.
- It alloys with iron, titanium and niobium are very useful.
- 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
Ammunition Industry
Chemical Industry
Medical Uses
NA
Medical Research
Other Uses
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
Alloys
Biological Properties
Toxicity
Toxic
Highly Toxic
Present in Human Body
No
Yes
In Blood
Not Available
0.00 Blood/mg dm-3
34
In Bone
Not Available
0.00 p.p.m.
33
Physical Properties
Melting Point
2,150.00 °C
10
303.50 °C
99+
Boiling Point
5,400.00 °C
5
1,457.00 °C
99+
Appearance
Physical State
Solid
Solid
Color
Gray
Silvery White
Luster
Metallic
NA
Hardness
Mohs Hardness
5.50
7
1.20
20
Brinell Hardness
1,450.00 MPa
6
26.50 MPa
99+
Vickers Hardness
1,520.00 MPa
5
Not Available
Speed of Sound
3,010.00 m/s
27
818.00 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 Properties
Chemical Formula
Hf
Tl
Isotopes
Known Isotopes
32
7
32
7
Electronegativity
Pauling Electronegativity
1.30
32
1.62
21
Sanderson Electronegativity
Not Available
2.25
5
Allred Rochow Electronegativity
1.23
25
1.44
17
Mulliken-Jaffe Electronegativity
Not Available
1.96
6
Allen Electronegativity
1.16
37
1.79
13
Electropositivity
Pauling Electropositivity
2.70
22
2.38
33
Ionization Energies
1st Energy Level
658.50 kJ/mol
40
589.40 kJ/mol
99+
2nd Energy Level
1,440.00 kJ/mol
99+
1,971.00 kJ/mol
14
3rd Energy Level
2,250.00 kJ/mol
99+
2,878.00 kJ/mol
32
4th Energy Level
3,216.00 kJ/mol
99+
Not Available
Electrochemical Equivalent
1.66 g/amp-hr
99+
7.63 g/amp-hr
2
Electron Work Function
3.90 eV
27
3.84 eV
28
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
72
99+
81
35
Electron Configuration
[Xe] 4f14 5d2 6s2
[Xe] 4f14 5d10 6s2 6p1
Crystal Structure
Hexagonal Close Packed (HCP)
Hexagonal Close Packed (HCP)
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
72
99+
81
35
Number of Neutrons
106
29
123
20
Number of Electrons
72
99+
81
35
Radius of an Atom
Atomic Radius
159.00 pm
28
170.00 pm
22
Covalent Radius
175.00 pm
23
145.00 pm
39
Van der Waals Radius
200.00 pm
28
196.00 pm
30
Atomic Weight
178.49 amu
39
204.38 amu
31
Atomic Volume
13.60 cm3/mol
38
17.20 cm3/mol
31
Adjacent Atomic Numbers
Valence Electron Potential
81.00 (-eV)
16
9.60 (-eV)
99+
Lattice Constant
319.64 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
1.58
12
1.60
6
Mechanical Properties
Density
Density At Room Temperature
13.31 g/cm3
26
11.85 g/cm3
31
Density When Liquid (at m.p.)
12.00 g/cm3
12
11.22 g/cm3
13
Tensile Strength
445.00 MPa
8
Not Available
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
Not Available
16.90 (Pa)
5
Vapor Pressure at 2000 K
0.00 (Pa)
24
Not Available
Elasticity properties
Shear Modulus
30.00 GPa
23
2.80 GPa
99+
Bulk Modulus
110.00 GPa
15
43.00 GPa
28
Young's Modulus
78.00 GPa
25
8.00 GPa
99+
Poisson Ratio
0.37
7
0.45
2
Other Mechanical Properties
Ductile, Malleable
Ductile, Sectile
Magnetic Properties
Magnetic Characteristics
Specific Gravity
13.31
18
11.85
22
Magnetic Ordering
Paramagnetic
Diamagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
331.00 nΩ·m
14
0.18 nΩ·m
99+
Electrical Conductivity
0.03 106/cm Ω
39
0.06 106/cm Ω
32
Electron Affinity
0.00 kJ/mol
40
19.20 kJ/mol
32
Thermal Properties
Specific Heat
0.14 J/(kg K)
37
0.13 J/(kg K)
39
Molar Heat Capacity
25.73 J/mol·K
36
26.32 J/mol·K
29
Thermal Conductivity
23.00 W/m·K
99+
46.10 W/m·K
33
Critical Temperature
Not Available
Not Available
Thermal Expansion
5.90 µm/(m·K)
99+
29.90 µm/(m·K)
12
Enthalpy
Enthalpy of Vaporization
661.10 kJ/mol
5
162.10 kJ/mol
99+
Enthalpy of Fusion
25.10 kJ/mol
8
4.27 kJ/mol
99+
Enthalpy of Atomization
703.00 kJ/mol
5
179.90 kJ/mol
99+
Standard Molar Entropy
43.60 J/mol.K
34
64.20 J/mol.K
19
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