Ruthenium-99 Mossbauer spectroscopy

Mossbauer spectroscopy is a specialist characterization tool in catalysis. Nevertheless, it has yielded essential information on a number of important catalysts, such as the iron catalyst for ammonia and Fischer-Tropsch synthesis, as well as the CoMoS hydrotreating catalyst. Mossbauer spectroscopy provides the oxidation state, the internal magnetic field, and the lattice symmetry of a limited number of elements such as iron, cobalt, tin, iridium, ruthenium, antimony, platinum and gold, and can be applied in situ. 

Kistner et al. [109] were the first to observe the Mossbauer effect in Ru. Kistner also reported the Mossbauer spectroscopy study of ruthenium compounds and alloys [110]. 

The precursor of ° Ru is ° Rh (tip, = 3 years). It is prepared by irradiating natural ruthenium metal with 20 MeV deuterons, " Ru (d, n) Rh. The target is then allowed to decay for several months to diminish the accompanying Rh activity. In a report on ° Ru Mossbauer spectroscopy [111], the authors reported on spectra of Ru metal, RuOa, and [Ru(NH3)4(HS03)2] at liquid helium temperature in standard transmission geometry using a Ge(Li) diode to detect the 127 keV y-rays. The absorber samples contained 1 g of ruthenium per cm. ... 

Dr. Erickson For those interested in coordination chemistry, certain other transition metal atoms are suitable for Mossbauer spectroscopy. One in particular is ruthenium which is just below iron in the Periodic Table. It is a difficult isotope to work with since it requires helium temperatures almost exclusively. I don t know whether it is possible to work at nitrogen temperatures or not, but Kistner at Brookhaven has examined various ruthenium compounds from the 2-j- to the 8+ oxidation states with interesting results. These are not published yet, but at least his work offers the possibility of going down one element below the other in the Periodic Table to study chemical effects. Osmium, which is below ruthenium, can also be Mossbauered. Some sort of systematic study like this involving elements in the various transition series would be extremely interesting. 

There has been to some degree the belief that Mossbauer spectroscopy, although in principle an ideal technique for catalyst studies, for practical purposes can only be applied to problems in catalysis if the catalyst contains either iron or tin. Therefore, one of the main purposes of this review is to show how Mossbauer spectroscopy can be directly extended to many additional Mossbauer atoms or isotopes (such as antimony, europium, nickel, ruthenium, gold, and tungsten) and, perhaps more importantly, how the technique can be extended to obtain information about systems that do not contain a Mossbauer atom. ... 

Besides oxide supported Sn-Ru catalysts, carbon supported catalysts also find application in hydrogenation reactions. Sn Mossbauer spectroscopy was used to investigate the tin component of ruthenium and tin supported on activated carbon catalysts containing 2 wt. % ruthenium and having Sn/(Sn-f Ru) ratios between zero and 0.4. Four major components in the Sn Mossbauer spectra were attributed to both Sn(II) and Sn(IV) oxides and to Ru-SnOx species formed on the surface of ruthenium metal particles. In addition to this " Sn spectra reveal the presence of minor amounts of Ru3Sn7 alloy phase. ... 

Manganese(VI) complexes, 109-111 Manganese(VII) complexes, 109-111 Marcasite, 1240 Mercury compounds ruthenium complexes, 280 Mesoperrhenates, 198 Mesoporphyrin iron complexes, 1266 Methemerythrin, 254 Molybdenum-iron-sulfur complexes, 241 MOssbauer spectroscopy iron, 1181... 

Mossbauer spectroscopy is based on the observation that nuclei held rigidly in a lattice can undergo recoil-free emission and absorption of X-radiation the separation of nuclear energy levels can be measured with great accuracy, and it is possible to detect weak interactions between a nucleus and its electronic environment. This may reveal the chemical state of the atom or ion, but only a few nuclei are susceptible to the effect, most work having been done with iron ( Fe) and tin Sn) and a little with ruthenium... 

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