Speaker
Prof.
John McCloy
(Washington State University)
Description
Because of their radioactive nature, solid technetium-99 oxides have been rarely studied, and there is
a dearth of modern spectra and diffraction patterns in the literature. This publication aims to address
this by detailing a low-temperature synthesis method for pure, crystalline alkali pertechnetates,
along with complete analysis by static and magic-angle-spinning nuclear magnetic resonance, Raman,
neutron diffraction (ND), and X-ray absorption spectroscopy (XAS). Insight gained from these
studies brings a deeper understanding of the periodic chemistry of alkali (Na,K,Rb,Cs) pertechnetates.
Additionally, we report attempts to make 5- and 6-coordinate pertechnetate compounds of K, Na,
and Li, i.e. TcO5 - and TcO6 -. It was found that higher coordinated species are very sensitive to
water, and easily decompose into their respective pertechnetates. It was difficult to obtain pure
compounds, but mixtures of the pertechnetate and other phases were frequently found, as evidenced
by XAS, ND, and Raman spectroscopy. Additionally, we summarize other work on Tc loading
in glasses, effect on glass structure, and salt formation in overloaded samples. For glasses, XAS
chemometrics based on principal component analysis and linear combination fitting suggests that Tc
is speciated first as isolated Tc4+, as Tc content is increased, there is more Tc7+ which partitions
first to K neighbors then to isolated sites. Preliminary work is reported assessing HTcO4 and related
compounds and their relationships to mechanisms of Tc volatility
Primary author
Prof.
John McCloy
(Washington State University)
Co-authors
Dr
Chuck Soderquist
(Pacific Northwest National Laboratory)
Dr
Jamie Wesver
(Washington State University)
