Actinium Hafnium Comparison
Periodic Table
Symbol
Ac
Hf
Group Number
Not Available
4
14
Period Number
7
6
Block
f block
d block
Element Family
Actinide
Transition Metal
CAS Number
7440348
99+
7440586
30
Space Group Name
Fm_ 3m
P63/mmc
Space Group Number
225.00
2
194.00
5
Facts
Interesting Facts
Not Available
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
Sources
Obtained by Treating Radium with Neutrons, Ores of metals
By-product Zirconium Refining
History
Who Discovered
Friedrich Oskar Giesel
Dirk Coster and George de Hevesy
Discovery
In 1902
In 1922
Abundance
Abundance In Universe
Not Available
7 * 10-8 %
25
Abundance In Sun
~-9999 %
~0.0000001 %
26
Abundance In Meteorites
Not Available
0.00 %
37
Abundance In Earth's Crust
Not Available
0.00 %
31
Abundance In Oceans
Not Available
0.00 %
27
Uses
Uses & Benefits
- Actinium metal has a great source of alpha rays but it is hardly used outside research purpose.
- 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.
Industrial Uses
NA
Ammunition Industry
Medical Uses
NA
NA
Other Uses
Alloys, Nuclear Research, Research Purposes
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
Biological Properties
Toxicity
Toxic
Toxic
Present in Human Body
No
No
In Blood
0.00 Blood/mg dm-3
37
Not Available
In Bone
0.00 p.p.m.
36
Not Available
Physical Properties
Melting Point
1,227.00 °C
38
2,150.00 °C
10
Boiling Point
3,200.00 °C
26
5,400.00 °C
5
Appearance
Physical State
Solid
Solid
Color
Silvery White
Gray
Luster
NA
Metallic
Hardness
Mohs Hardness
Not Available
5.50
7
Brinell Hardness
Not Available
1,450.00 MPa
6
Vickers Hardness
Not Available
1,520.00 MPa
5
Speed of Sound
Not Available
3,010.00 m/s
27
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
Ac
Hf
Isotopes
Known Isotopes
29
10
32
7
Electronegativity
Pauling Electronegativity
1.10
99+
1.30
32
Allred Rochow Electronegativity
1.00
36
1.23
25
Allen Electronegativity
Not Available
1.16
37
Electropositivity
Pauling Electropositivity
2.90
10
2.70
22
Ionization Energies
1st Energy Level
499.00 kJ/mol
99+
658.50 kJ/mol
40
2nd Energy Level
1,170.00 kJ/mol
99+
1,440.00 kJ/mol
99+
3rd Energy Level
1,900.00 kJ/mol
99+
2,250.00 kJ/mol
99+
4th Energy Level
4,700.00 kJ/mol
23
3,216.00 kJ/mol
99+
Electrochemical Equivalent
2.82 g/amp-hr
18
1.66 g/amp-hr
99+
Electron Work Function
Not Available
3.90 eV
27
Other Chemical Properties
Ionization, Radioactive Isotopes, Radioactivity, Solubility
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
89
29
72
99+
Electron Configuration
[Rn] 6d1 7s2
[Xe] 4f14 5d2 6s2
Crystal Structure
Face Centered Cubic (FCC)
Hexagonal Close Packed (HCP)
Crystal Lattice
FCC-Crystal-Structure-of-Actinium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
89
29
72
99+
Number of Neutrons
138
16
106
29
Number of Electrons
89
29
72
99+
Radius of an Atom
Atomic Radius
195.00 pm
7
159.00 pm
28
Covalent Radius
Not Available
175.00 pm
23
Van der Waals Radius
Not Available
200.00 pm
28
Atomic Weight
227.00 amu
25
178.49 amu
39
Atomic Volume
22.54 cm3/mol
11
13.60 cm3/mol
38
Adjacent Atomic Numbers
Valence Electron Potential
38.60 (-eV)
99+
81.00 (-eV)
16
Lattice Constant
567.00 pm
8
319.64 pm
99+
Lattice Angles
π/2, π/2, π/2
π/2, π/2, 2 π/3
Lattice C/A Ratio
Not Available
1.58
12
Mechanical Properties
Density
Density At Room Temperature
10.00 g/cm3
37
13.31 g/cm3
26
Density When Liquid (at m.p.)
Not Available
12.00 g/cm3
12
Tensile Strength
Not Available
445.00 MPa
8
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 2000 K
Not Available
0.00 (Pa)
24
Elasticity properties
Shear Modulus
Not Available
30.00 GPa
23
Bulk Modulus
Not Available
110.00 GPa
15
Young's Modulus
Not Available
78.00 GPa
25
Poisson Ratio
Not Available
0.37
7
Other Mechanical Properties
NA
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
10.07
28
13.31
18
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Unknown
Conductor
Resistivity
Not Available
331.00 nΩ·m
14
Electrical Conductivity
Not Available
0.03 106/cm Ω
39
Electron Affinity
Not Available
0.00 kJ/mol
40
Thermal Properties
Specific Heat
0.12 J/(kg K)
40
0.14 J/(kg K)
37
Molar Heat Capacity
27.20 J/mol·K
18
25.73 J/mol·K
36
Thermal Conductivity
12.00 W/m·K
99+
23.00 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
Not Available
5.90 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
Not Available
661.10 kJ/mol
5
Enthalpy of Fusion
Not Available
25.10 kJ/mol
8
Enthalpy of Atomization
301.00 kJ/mol
36
703.00 kJ/mol
5
Standard Molar Entropy
56.50 J/mol.K
25
43.60 J/mol.K
34
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