Gas-phase isothermal chromatography with short-lived technetium isotopes

Gas-phase chemistry of ruthenium and rhodium carbonyl complexes

Short-lived ruthenium and rhodium isotopes were produced from a (252)Cf spontaneous fission (SF) source. Their volatile carbonyl complexes were formed in gas-phase reactions in situ with the carbon-monoxide containing gas. A gas-jet system was employed to transport the volatile carbonyls from the recoil chamber to the chemical separation apparatus. The gas-phase chemical behaviors of these carbonyl complexes were studied using an online low temperature isothermal chromatography (IC) technique. Long IC columns made up of FEP Teflon were used to obtain the chemical information of the high-volatile Ru and Rh carbonyls. By excluding the influence of precursor effects, short-lived isotopes of (109-110)Ru and (111-112)Rh were used to represent the chemical behaviours of Ru and Rh carbonyls. Relative chemical yields of about 75% and 20% were measured for Ru(CO)5 and Rh(CO)4, respectively, relative to the yields of KCl aerosols transported in Ar gas. The adsorption enthalpies of ruthenium and rhodium carbonyl complexes on a Teflon surface were determined to be around ΔHads = -33(+1)(-2) kJ mol(-1) and -36(+2)(-1) kJ mol(-1), respectively, by fitting the breakthrough curves of the corresponding carbonyl complexes with a Monte Carlo simulation program. Different from Mo and Tc carbonyls, a small amount of oxygen gas was found to be not effective for the chemical yields of ruthenium and rhodium carbonyl complexes. The general chemical behaviors of short-lived carbonyl complexes of group VI-IX elements were discussed, which can be used in the future study on the gas-phase chemistry of superheavy elements - Bh, Hs, and Mt carbonyls.

Gas-phase chemistry of technetium carbonyl complexes

Relative chemical yields and adsorption enthalpies on quartz and Teflon surfaces for short-lived Tc carbonyl complexes were obtained.

Nuclear and radiochemistry in China: present status and future perspectives

Nuclear and radiochemistry is one of the frontier areas of chemistry with high impact on national security, energy supply, scientific advances, social and economic development. Nuclear and radiochemistry in China is now experiencing a renaissance, which is being strongly motivated by China’s huge demand for nuclear energy. With this in review, the progress in nuclear and radiochemistry of China is selectively addressed. Some hot topics have been summarized and the main research results achieved by Chinese scientists in this field are highlighted, with emphasis on the basic nuclear chemistry, actinide and trans-actinide chemistry, chemistry of spent nuclear fuel reprocessing, radioanalytical chemistry, environmental radiochemistry and radiopharmaceutical chemistry, etc. Some measures about how to promote the radiochemical education and research in China are suggested, and future perspectives are briefly outlined as well.

On-line gas chromatographic studies of Nb, Ta, and Db bromides

The isothermal gas chromatographic behaviour of the group 5 elements Nb, Ta and Db was investigated in a brominating atmosphere using the OLGA technique. It was found that Db forms a very volatile compound, most likely the pentabromide, being more volatile than similar compounds formed under identical conditions with Nb and Ta, respectively. This observation is in disagreement with previous experimental investigations of the same compound but in agreement with theoretical prediction.