Gas-phase chemistry of technetium carbonyl complexes
Gas-phase chemical behaviors of short-lived technetium carbonyl complexes were studied using a low temperature isothermal chromatograph (IC) coupled with a 252 Cf spontaneous fission (SF) source. Fission products recoiled from the 252 Cf SF source were thermalized in a mixed gas containing CO, and t...
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Veröffentlicht in: | Physical chemistry chemical physics : PCCP 2015-05, Vol.17 (2), p.13228-13234 |
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Sprache: | eng |
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Zusammenfassung: | Gas-phase chemical behaviors of short-lived technetium carbonyl complexes were studied using a low temperature isothermal chromatograph (IC) coupled with a
252
Cf spontaneous fission (SF) source. Fission products recoiled from the
252
Cf SF source were thermalized in a mixed gas containing CO, and then technetium carbonyl complexes were formed from reactions between CO gas and various technetium isotopes. A gas-jet system was employed to transport the volatile carbonyl complexes from a recoil chamber to the IC. Short IC columns made of Fluorinated Ethylene Propylene (FEP) Teflon and quartz were used to obtain chemical information about the technetium carbonyl complexes. The results for the
104
Tc-
106
Tc carbonyl complexes were found to be strongly influenced by the precursors, and showed the chemical behaviors of
104
Mo-
106
Mo carbonyl complexes, respectively. However,
107
Tc and
108
Tc could represent the chemical information of the element technetium due to their high independent yields and the very short half-lives of their precursors
107
Mo and
108
Mo. An adsorption enthalpy of about Δ
H
ads
= −43 kJ mol
−1
was determined for the Tc carbonyl complexes on both the Teflon and quartz surfaces by fitting the breakthrough curves of the
107
Tc and
108
Tc carbonyl complexes with a Monte Carlo simulation program. Chemical yields of around 25% were measured for the Tc carbonyl complexes relative to the transport yields obtained with the gas-jet transport of KCl aerosol particles with Ar carrier gas. Furthermore, the influence of a small amount of O
2
gas on the yields of the Mo and Tc carbonyl complexes was studied.
Relative chemical yields and adsorption enthalpies on quartz and Teflon surfaces for short-lived Tc carbonyl complexes were obtained. |
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ISSN: | 1463-9076 1463-9084 |
DOI: | 10.1039/c5cp00979k |