Saturday, March 21, 2015

Technetium Chemistry in the Fuel Cycle: Combining Basic and Applied Studies #chempaperaday 204

Technetium is the most mysterious element. In the middle of the d-block and yet radioactive. You can't just dig and find technetium (therefore the name). Despite all these difficulties, the isotope 99mTc is the "workhorse of diagnostic nuclear medicine." It is the byproduct of fission reactions of uranium isotopes in the reactors. Because, it requires special handling and other requirements, not every lab is lucky to study technetium chemistry. So, not much is known about it yet. All I know is that it makes nice bimetallic complexes with multiple Tc-Tc bonds. So, I was not much surprised to learn that "[on binary compounds]...only three species, TcF6, TcF5, and TcCl4, identified prior to 2008."

A few more details from the paper:

Because of its high fission production rate, the amount of technetium on Earth may ultimately exceed that of rhenium, its heavier congener.  

In a typical light water nuclear reactor, 99Tc production is around 2 g/day for every 100 MW of thermal energy. 

Technetium has a range of oxidation states, from 7+ to 1–, and its chemistry has considerable similarities to rhenium; e.g., it has extensive pentavalent chemistry. 

The overall trends clearly demonstrate increasing technetium–technetium interactions with decreasing oxidation state.

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