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72 Hf
Element Revision Sheet

Hafnium (Hf)

Transition Metals Block D Group 4 • Period 6
Superhero Identity

"The Zirconium Twin, a hero almost identical to its twin, tasked with controlling nuclear reactions in submarines."

A memorable persona to anchor Hf in your mind.

Density

13.31

Grams per cm³

Melting Point

2233

Celsius (°C)

Atomic Radius

212

Radius (pm)

Everyday Connection

Daily Life Link

Hafnium is found in the control rods in a nuclear submarine�s reactor.

Discovery & History

Year Discovered

1923

Discovered By

Dirk Coster & George de Hevesy

Origin of Name

"The name is derived from the Latin name for Copenhagen, ''Hafnia''"

Technical Properties

Atomic Mass

178.486 u

Standard State

solid

Boiling Point

4600°C

Electron Configuration

[Xe] 4f145d26s2

1st Ionization Energy

6.825 eV

Electron Affinity

N/A

Oxidation States

[+4]
Appearance

"Hafnium is a lustrous, silvery, ductile metal."

Did You Know?

1

It was one of the last stable (non-radioactive) elements to be discovered, in 1923.

2

Its chemical properties are so similar to zirconium that it is extremely difficult to separate the two. For this reason, zirconium metal always contains a small amount of hafnium unless it has been highly purified.

3

Hafnium is excellent at absorbing neutrons, so it is used to make control rods for nuclear submarines.

4

It is named after Hafnia, the Latin name for Copenhagen, the city where it was discovered.

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