Hafnium

Images

Image

Attribution: Alchemist-hp

Animated Hafnium

History

From Hafinia, the Latin name for Copenhagen. Many years before its discovery in 1923 (credited to D. Coster and G. von Hevesey), Hafnium was thought to be present in various minerals and concentrations. On the basis of the Bohr theory, the new element was expected to be associated with zirconium.

It was finally identified in zircon from Norway, by means of X-ray spectroscope analysis. It was named in honor of the city in which the discovery was made. Most zirconium minerals contain 1 to 5 percent hafnium.

It was originally separated from zirconium by repeated recrystallization of the double ammonium or potassium fluorides by von Hevesey and Jantzen. Metallic hafnium was first prepared by van Arkel and deBoer by passing the vapor of the tetraiodide over a heated tungsten filament. Almost all hafnium metal now produced is made by reducing the tetrachloride with magnesium or with sodium (Kroll Process).

Uses

Because the element not only has a good absorption cross section for thermal neutrons (almost 600 times that of zirconium), but also A nuclear submarineexcellent mechanical properties and is extremely corrosion-resistant, hafnium is used for reactor control rods. Such rods are used in nuclear submarines.

Hafnium is used in gas-filled and incandescent lamps, and is an efficient getter for scavenging oxygen and nitrogen.

General Info

AtomicNumber
72
Symbol
Hf
Name
Hafnium

Atomic Info

Appearance
AtomicWeight
178.49(2)
Color
4DC2FF
ElectronicConfiguration
[Xe] 4f14 5d2 6s2
ElectronegativityInPauling
1.3
AtomicRadiusInPM
150
IonRadiusInPM
71 (+4)
VanDerWaalsRadiusInPM
IEinKJmol
659
EAinKJmol
0
OxidationStates
2, 3, 4
StandardState
solid
BondingType
metallic
MeltingPoint
2506
BoilingPoint
4876
Density
13.31
State
Transition metal
DiscoveredYear
1923