An Overview about the Chemical Element Hassium


Symbol: Hs

Atomic Number: 108

Atomic Mass: 277 amu (atomic mass units)

Melting Point: Unknown

Boiling Point: Unknown

Number of Protons: 108

Number of Electrons: 108

Number of Neutrons: 169

Classification: Transition Metal (Man Made)

Crystal Structure: Unknown

Density @ 293K: Unknown

Color: Unknown

The first atoms to be produced of a new radioactive “super heavy” element with the atomic mass of 108 were reported in 1984. The German team of scientists led by Peter Armbruster and Gottfried Munzenber were working at the Gesellschaft fur Schwerionenforschung (GSI) in Darmstadt, in Germany. Using a linear accelerator they bombarded a target made of lead-208 atoms with ions of iron-58. These high speed collisions overcame the forces which normally keep the nuclei of two atoms apart leading to the formation of atoms of hassium-265. With each atom of hassium formed one free neutron was released. The newly formed isotope had a half-life of 2.3 milliseconds. The atoms decayed by either alpha decay or spontaneous fission.

Until the Germans work could be confirmed the element was given the name unniloctium and the symbol Uno under the International Union for Pure and Applied Chemistry (IUPAC) system of holding names for new elements. Hassium’s name comes from the Latin name for the German state Hessen “Hassias”. The GSI is based in Hessen.

Other isotopes of hassium have now been produced all of which are unstable. They have mass numbers that range from 263 to 277. To date the most stable isotope discovered is hassium-277. This isotope has a half-life of 12 minutes. It decays by alpha decay, to form seaborgium-273, or by spontaneous fission. The shortest half-life measured is that of hassium-264 at 0.8 milliseconds. Hassium-264 also decays by alpha decay or spontaneous fission.

As only a few atoms of hassium have ever been produced and they all decay so quickly it has not been able to measure any of the element’s bulk properties. From its position in the periodic table (Group 8 and Period 7) it is thought that any quantity of the element would be metallic and silver or gray in color. It is quite likely that it would have chemical properties similar to those of the element osmium.

The methods used to make “super heavy” elements can produce only a few atoms at a time. This means that it is extremely unlikely that hassium will ever have any industrial applications. The element is valuable to laboratories around the world researching the field of “super heavy” elements.


Web Elements

National Nuclear Data Center