Hafnium is a chemical element in the Periodic Table marked with the atomic number of 72 and with the chemical symbol Hf. This chemical element belongs to period 6 elements and the Transition Metals category. Similar to the rest of the Transition Metal elements Hafnium possesses various metallic properties. In the Periodic Table Hafnium is preceded by Lutetium and is followed by Tantalum.
Hafnium is a relatively reactive chemical element, which ignites spontaneously in air and oxidizes with Halogens. It is quite resistant to Alkali elements and acids. This metallic element is rather similar to another Transition Metal – Zirconium – and never exists freely in nature as a free element. It can be found mostly in Zircon ores, sand ores, and carbonatite intrusions. Hafnium is among the most difficult chemical elements when it comes to separation, especially when it is combined with Zirconium. This Transition Metal is pyrophoric and should be taken with care. It has various applications leading towards metallurgy, microprocessor manufacturing, nuclear science and geochemistry.
Physical Characteristics of Hafnium
In terms of physical characteristics Hafnium shares some group trends with the rest of the Transition Metals in the Periodic Table and is quite similar to another Transition Metal – Zirconium. Hafnium is a ductile metal, which appears as a shiny, silvery solid, which remains resistant to corrosion. It has various nuclear properties and the most important of them is Hafnium’s extremely high thermal neutron-capture cross-section. It has a relatively low density and noteworthy high melting and boiling points – at 2506 K and 4876 K in their respective order. Hafnium crystalizes in a typical hexagonal close-packed crystal structure and has a paramagnetic magnetic ordering.
Chemical Properties of Hafnium
Atomic Number – 72
Group – 4
Period – 6
Block – d
Electronic Configuration – 4f14 5d2 6s2
Relative Atomic Mass – 178.49 (178.49 g/mol)
Molecular Weight – 178.49
Electronegativity – 1.3
Density (G CM-3) – 13.31 g/cm3 at room temperature; 12 g/cm3 in liquid state
Melting Point – 2506 K; 2233 °C; 4051 °F
Boiling Point – 4876 K; 4603 °C; 8317 °F
Atomic Radius – 159 pm
Isotopes – 5
Electronic Shell – 2, 8, 18, 32, 10, 2
Discovery of Hafnium
A large number of chemists and scientists have tried to discover the element Hafnium between 1869, when Dmitri Mendeleev predicted the existence of this chemical element, and 1922 when it was indeed discovered. The two scientists, who are officially credited with the discovery of Hafnium, are the Dutch physicist Dirk Coster and the Hungarian radiochemist Georg von Hevesy. They made their finding in Copenhagen, Denmark, where they examined various Zirconium ores. Hevesy and Coster named the new element after the Latin name for the city of Copenhagen – Hafnia.
The very first metallic production of Hafnium was carried out in 1924 and the same method, which was used then, is also used nowadays for the separation of Hafnium from Zirconium.
Recognized by: Dirk Coster and Georg von Hevesy (1922)
Known and discovered by: Dirk Coster and Georg von Hevesy (1922)
Named by: Dirk Coster and Georg von Hevesy
Uses and role of Hafnium
Due to the fact that Hafnium is short on abundance and that it is difficult to separate it from Zirconium, it does not have many uses and applications rather than just a few. Most industries use Zirconium as a substitute to Hafnium. However, this Transition Metal still finds application in metallurgy, in geochemistry, and in nuclear science.
For example, Hafnium plays a big role in the manufacturing of nuclear reactors as parts of the control rods. It is also used in metallurgy when alloyed with various chemical elements, including Tantalum, Iron, Titanium and Niobium. Hafnium finds application in microprocessor manufacturing and also in incandescent lamps.
Hafnium on Earth
As a Transition Metal, Hafnium is a rare element on Earth. Its abundance in the Earth’s crust is quite low and it never exists as a free element. Hafnium can be found mainly in Zirconium ores, pegmatite ores, carbonatite intrusions, and mineral sand ores. The main deposits of Hafnium are found in the Earth’s upper crust.
It has been recently discovered that Hafnium’s nuclear isomeric isotope 178m2HF could be used in the manufacturing of lethal nuclear weapons. Another discovery claims that garnet minerals, which are abundant on Hafnium, can be applied when dating metamorphic events.