Minimale Verunreinigungen beeinflussen chemisches Verhalten einer seltenen Erden-Verbindung

Minimal Impurities Affect the ChemicalBbehavior of a Rare Earth Compound

Tiny contamination with the radioactive element americium of a chemical substance can have great effects-this is the result of a German-Austrian research team headed by Prof. Dr. Georg Steinhauser from the Institute of Radioecology and Radiation Protection.

In the past, it has been assumed in chemistry that minimal traces of another element have no influence on the crystallization behavior or the chemical structure of a substance, so the experiment - at least for the element americium - has disproved this assumption.

The research group has achieved groundbreaking proof in its current work: The scientists were able to show that an ultra trace contamination of the radioactive element americium drastically influences the chemical behavior of a compound of rare earths terbium. Terbium is a representative of the heavy rare earths. The work shows that one americium atom dictates half a billion terbium atoms to behave like a light rare earth. "At first we could not explain the strange crystallization behavior. Too absurd, the idea seemed that a few atoms could dominate the entire crystal," says Prof. Georg Steinhauser. Around 100 experiments over a long period of time confirmed the scientists'' assumption that the americium atom influences the behavior of terbium as if its atomic weight had decreased. In the periodic table of the elements, the terbium seems to slip further forward into the area of the light rare earths.

Americium is a radioactive element and therefore easily measurable. This fact only has made the proof possible.

This result may influence the design criteria of a radioactive waste repository. So far, only the influence of different environmental conditions on the migration behavior of radioactive waste - among others americium - has been investigated. "

Our work has shown that, under certain conditions, it is important to consider how radioactive waste can change its environment. This is a view that seemed previously unthinkable. With this knowledge, we have taken an important step towards a safe repository," Professor Steinhauser explains.

The publication on this topic can be found at:

For further questions please contact:

Prof. Dr. Georg Steinhauser
Leibniz Universität Hannover
Institut für Radioökologie und Strahlenschutz