Holmium Hafnium Comparison
Periodic Table
Symbol
Ho
Hf
Group Number
Not Available
4
14
Period Number
6
6
Block
f block
d block
Element Family
Lanthanide
Transition Metal
CAS Number
7440600
29
7440586
30
Space Group Name
P63/mmc
P63/mmc
Space Group Number
194.00
5
194.00
5
Facts
Interesting Facts
- Holmium metal is very soft and malleable.
- Holmium metal is well known for its corrosion resistivity.
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
Sources
Found in Minerals, Mining, Ores of Minerals
By-product Zirconium Refining
History
Who Discovered
Marc Delafontaine
Dirk Coster and George de Hevesy
Discovery
In 1878
In 1922
Abundance
Abundance In Universe
5 * 10-8 %
27
7 * 10-8 %
25
Abundance In Sun
~-9999 %
~0.0000001 %
26
Abundance In Meteorites
0.00 %
99+
0.00 %
37
Abundance In Earth's Crust
0.00 %
38
0.00 %
31
Abundance In Oceans
0.00 %
99+
0.00 %
27
Uses
Uses & Benefits
- Holmium metal has an ability to absorb neutrons, so this metal is used in nuclear reactors to keep the chain reactions of elements under control.
- Alloys of Holmium are used to produce Magnet.
- 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
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
Biological Properties
Toxicity
Low Toxic
Toxic
Present in Human Body
No
No
Physical Properties
Melting Point
1,461.00 °C
30
2,150.00 °C
10
Boiling Point
2,600.00 °C
99+
5,400.00 °C
5
Appearance
Physical State
Solid
Solid
Color
Silvery White
Gray
Luster
Metallic
Metallic
Hardness
Mohs Hardness
Not Available
5.50
7
Brinell Hardness
746.00 MPa
13
1,450.00 MPa
6
Vickers Hardness
481.00 MPa
23
1,520.00 MPa
5
Speed of Sound
2,760.00 m/s
30
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
Ho
Hf
Isotopes
Known Isotopes
34
5
32
7
Electronegativity
Pauling Electronegativity
1.23
37
1.30
32
Allred Rochow Electronegativity
1.10
30
1.23
25
Allen Electronegativity
Not Available
1.16
37
Electropositivity
Pauling Electropositivity
2.77
17
2.70
22
Ionization Energies
1st Energy Level
581.00 kJ/mol
99+
658.50 kJ/mol
40
2nd Energy Level
1,140.00 kJ/mol
99+
1,440.00 kJ/mol
99+
3rd Energy Level
2,204.00 kJ/mol
99+
2,250.00 kJ/mol
99+
4th Energy Level
4,100.00 kJ/mol
34
3,216.00 kJ/mol
99+
Electrochemical Equivalent
2.02 g/amp-hr
29
1.66 g/amp-hr
99+
Electron Work Function
Not Available
3.90 eV
27
Other Chemical Properties
Chemical Stability, Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
Atomic Properties
Atomic Number
67
99+
72
99+
Electron Configuration
[Xe] 4f11 6s2
[Xe] 4f14 5d2 6s2
Crystal Structure
Hexagonal Close Packed (HCP)
Hexagonal Close Packed (HCP)
Crystal Lattice
HCP-Crystal-Structure-of-Holmium.jpg#100
BCC-Crystal-Structure-.jpg#100
Atom
Number of Protons
67
99+
72
99+
Number of Neutrons
98
34
106
29
Number of Electrons
67
99+
72
99+
Radius of an Atom
Atomic Radius
176.00 pm
18
159.00 pm
28
Covalent Radius
192.00 pm
17
175.00 pm
23
Van der Waals Radius
216.00 pm
24
200.00 pm
28
Atomic Weight
164.93 amu
99+
178.49 amu
39
Atomic Volume
18.70 cm3/mol
24
13.60 cm3/mol
38
Adjacent Atomic Numbers
Valence Electron Potential
47.90 (-eV)
31
81.00 (-eV)
16
Lattice Constant
357.73 pm
38
319.64 pm
99+
Lattice Angles
π/2, π/2, 2 π/3
π/2, π/2, 2 π/3
Lattice C/A Ratio
1.57
17
1.58
12
Mechanical Properties
Density
Density At Room Temperature
8.79 g/cm3
99+
13.31 g/cm3
26
Density When Liquid (at m.p.)
8.34 g/cm3
26
12.00 g/cm3
12
Tensile Strength
Not Available
445.00 MPa
8
Viscosity
Not Available
Not Available
Vapor Pressure
Vapor Pressure at 1000 K
0.00 (Pa)
16
Not Available
Vapor Pressure at 2000 K
Not Available
0.00 (Pa)
24
Elasticity properties
Shear Modulus
26.30 GPa
28
30.00 GPa
23
Bulk Modulus
40.20 GPa
32
110.00 GPa
15
Young's Modulus
64.80 GPa
31
78.00 GPa
25
Poisson Ratio
0.23
29
0.37
7
Other Mechanical Properties
Ductile, Malleable, Sectile
Ductile, Malleable
Magnetic Properties
Magnetic Characteristics
Specific Gravity
8.80
35
13.31
18
Magnetic Ordering
Paramagnetic
Paramagnetic
Electrical Properties
Electrical Property
Conductor
Conductor
Resistivity
814.00 nΩ·m
4
331.00 nΩ·m
14
Electrical Conductivity
0.01 106/cm Ω
99+
0.03 106/cm Ω
39
Electron Affinity
50.00 kJ/mol
21
0.00 kJ/mol
40
Thermal Properties
Specific Heat
0.16 J/(kg K)
35
0.14 J/(kg K)
37
Molar Heat Capacity
27.15 J/mol·K
19
25.73 J/mol·K
36
Thermal Conductivity
16.20 W/m·K
99+
23.00 W/m·K
99+
Critical Temperature
Not Available
Not Available
Thermal Expansion
11.20 µm/(m·K)
35
5.90 µm/(m·K)
99+
Enthalpy
Enthalpy of Vaporization
241.00 kJ/mol
38
661.10 kJ/mol
5
Enthalpy of Fusion
11.76 kJ/mol
29
25.10 kJ/mol
8
Enthalpy of Atomization
301.00 kJ/mol
36
703.00 kJ/mol
5
Standard Molar Entropy
75.30 J/mol.K
8
43.60 J/mol.K
34
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