Symbol
Hf
  
Au
  
Period Number
6
  
6
  
Block
d block
  
d block
  
Element Family
Transition Metal
  
Transition Metal
  
Space Group Name
P63/mmc
  
Fm_ 3m
  
Interesting Facts
- Hafnium metal is highly reactive, hence not found free in nature.
- Hafnium metal as predicated after Mendeleev finished his periodic table.
  
- It is found in copper ores and from the crust of the earth.
- It is the most malleable and ductile metal.
- Gold alloys are used in Dentistry as fillings, crowning, clips, etc. It is also used as an artificial limb joints.
  
Sources
By-product Zirconium Refining
  
Earth's crust, Mining, Ores of metals
  
History
  
  
Who Discovered
Dirk Coster and George de Hevesy
  
Unknown
  
Discovery
In 1922
  
Before 6000 BCE
  
Abundance
  
  
Abundance In Sun
~0.0000001 %
  
26
~0.0000001 %
  
26
Abundance In Earth's Crust
Abundance In Humans
Not Available
  
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.
  
- Gold metal is mainly used for Jewelry, bullion, coinage, etc.
- It is used in the art, decoration, ornaments, etc. It is also used for electroplating process.
  
Industrial Uses
Ammunition Industry
  
Chemical Industry, Clothing Industry, Electrical Industry, Electronic Industry
  
Medical Uses
NA
  
Dentistry, Pharmaceutical Industry
  
Other Uses
Alloys, In Nuclear Reactors, Nuclear Research, Research Purposes
  
Alloys, Bullion, Coinage, Jewellery, Sculptures, Statues
  
Biological Properties
  
  
Toxicity
Toxic
  
Non Toxic
  
Present in Human Body
No
  
Yes
  
In Blood
Not Available
  
0.00 Blood/mg dm-3
  
35
In Bone
Not Available
  
0.02 p.p.m.
  
30
Melting Point
2,150.00 °C
  
10
1,064.43 °C
  
99+
Boiling Point
2,807.00 °C
  
36
Appearance
  
  
Physical State
Solid
  
Solid
  
Color
Gray
  
Gold
  
Luster
Metallic
  
Metallic
  
Hardness
  
  
Brinell Hardness
1,450.00 MPa
  
6
194.00 MPa
  
99+
Vickers Hardness
1,520.00 MPa
  
5
Speed of Sound
3,010.00 m/s
  
27
2,030.00 m/s
  
99+
Optical Properties
  
  
Reflectivity
Not Available
  
Allotropes
No
  
No
  
α Allotropes
Not Available
  
Not Available
  
β Allotropes
Not Available
  
Not Available
  
γ Allotropes
Not Available
  
Not Available
  
Chemical Formula
Hf
  
Au
  
Isotopes
  
  
Electronegativity
  
  
Pauling Electronegativity
Allred Rochow Electronegativity
Mulliken-Jaffe Electronegativity
Not Available
  
Electropositivity
  
  
Pauling Electropositivity
Ionization Energies
  
  
1st Energy Level
658.50 kJ/mol
  
40
890.10 kJ/mol
  
8
2nd Energy Level
1,440.00 kJ/mol
  
99+
1,980.00 kJ/mol
  
12
3rd Energy Level
2,250.00 kJ/mol
  
99+
Not Available
  
4th Energy Level
3,216.00 kJ/mol
  
99+
Not Available
  
Electrochemical Equivalent
1.66 g/amp-hr
  
99+
2.45 g/amp-hr
  
21
Other Chemical Properties
Anti Corrosion, Ionization, Radioactive Isotopes, Solubility
  
Chemical Stability, Ionization, Solubility
  
Electron Configuration
[Xe] 4f14 5d2 6s2
  
[Xe] 4f14 5d10 6s1
  
Crystal Structure
Hexagonal Close Packed (HCP)
  
Face Centered Cubic (FCC)
  
Crystal Lattice
BCC-Crystal-Structure-.jpg#100
  
FCC-Crystal-Structure-of-Gold.jpg#100
  
Atom
  
  
Radius of an Atom
  
  
Atomic Volume
13.60 cm3/mol
  
38
10.20 cm3/mol
  
99+
Adjacent Atomic Numbers
  
  
Valence Electron Potential
81.00 (-eV)
  
16
43.40 (-eV)
  
99+
Lattice Angles
π/2, π/2, 2 π/3
  
π/2, π/2, π/2
  
Density
  
  
Density At Room Temperature
13.31 g/cm3
  
26
19.30 g/cm3
  
15
Density When Liquid (at m.p.)
12.00 g/cm3
  
12
Viscosity
Not Available
  
Not Available
  
Vapor Pressure
  
  
Vapor Pressure at 1000 K
Not Available
  
Elasticity properties
  
  
Other Mechanical Properties
Ductile, Malleable
  
Ductile, Malleable
  
Magnetic Characteristics
  
  
Magnetic Ordering
Paramagnetic
  
Diamagnetic
  
Electrical Properties
  
  
Electrical Property
Conductor
  
Conductor
  
Resistivity
331.00 nΩ·m
  
14
Electrical Conductivity
0.03 106/cm Ω
  
39
0.45 106/cm Ω
  
3
Electron Affinity
0.00 kJ/mol
  
40
222.80 kJ/mol
  
1
Specific Heat
0.14 J/(kg K)
  
37
0.13 J/(kg K)
  
39
Molar Heat Capacity
25.73 J/mol·K
  
36
25.42 J/mol·K
  
40
Thermal Conductivity
23.00 W/m·K
  
99+
318.00 W/m·K
  
3
Critical Temperature
Not Available
  
Not Available
  
Thermal Expansion
5.90 µm/(m·K)
  
99+
14.20 µm/(m·K)
  
26
Enthalpy
  
  
Enthalpy of Vaporization
661.10 kJ/mol
  
5
324.40 kJ/mol
  
27
Enthalpy of Fusion
25.10 kJ/mol
  
8
12.55 kJ/mol
  
27
Enthalpy of Atomization
703.00 kJ/mol
  
5
364.00 kJ/mol
  
25
Standard Molar Entropy
43.60 J/mol.K
  
34
47.40 J/mol.K
  
32