Spectroscopic Evidence for the Formation of the Mercurous Ion in Irradiated Acetates

Abstract

The Hg(1) center has been produced by y-irradiation both in HgQ doped cadmium acetate trihydrate and pure mercuric acetate. Both electron paramagnetic resonance and optical spectroscopy have been used to identify this species. The results indicate that the Hg(0 ion is produced in a covalent environment.La formation de HgO est produite par I'irradiation-y a la fois de Hg(I1) additionne d'acetate de cadmium trihydrate et d'adtate mercurique pur. Cette e s p k a eti identifik a la fois par resonance paramagnetique electronique et par spectroscopie optique. Les rksultats indiquent que l'ion Hg(0 est produit dans un environnement covalent.Canadian Journal of Chemistry, 49,2868 (1971) IntroductionThe effect of crystal structure on the production of radicals in irradiated acetates has been the subject of a recent publication (I). At 77 OK, the hydrated metal ,acetates gave methyl radicals as the primary product, whereas the anhydrous salts gave other species, usually the CH2C02-radical. The products of C-C bond rupture are stabilized by the hydrogen bond network present in hydrated salts. In this study the effect of the metal ion was ignored. However, recent results (2-4) have indicated that the metal ions can play an important role in the radiolysis of their salts. For example, it was necessary to invoke cationinvolvement to account for the unusual electron paramagnetic resonance (e.p.r.) spectra exhibited by polycrystalline Group IB and IIB metal carbonates and nitrates exposed to y-rays (2). The species (CdC0,)-, (Ag,CO,)-, (CdNO,), and (AgN0,)-, essentially covalent entities, were identified. Also, we recently reported that the exposure of the double salt CaCd(CH3.C02),6H,0 to y-rays at 77 O K resulted in the formation of Cd(1) and the methyl radical; on warming these centers decayed to produce the acetate fragment, CH2C02-(3,4). It would appear that the formation of low oxidation states of the metal ion, on irradiation, will occur when the cation present in the undamaged crystal has a high inelastic scattering cross section for electrons. The present investigation forms part of a comprehensive examination of the role of metal ions, which have

Stochastic Computing Chip for Measurement of Manhattan Distance

“…In figure 1, it may be noted that the 'parallel components' (a 1 to a 4 ) exhibit an m I dependence of linewidth in the temperature range 10-200 K. In addition to this signal, a sharp EPR signal with g iso = 2.0036 ± 0.0002 and another axially symmetric signal with g ⊥ = 1.9391 ± 0.0022, g = 1.8900 ± 0.0002, could also be seen in the figure in the above-mentioned temperature range. The sharp isotropic line, with g = 2.0036±0.0002, was assigned to the even isotope of the Hg + centre (5d 10 , 6s 1 ) [11] and the other line with g = 1.8900 ± 0.0002 and g ⊥ = 1.9391 + 0.0002 was assigned to Mo 5+ resonance.…”

Possible Identification of Pb1+ and PbH2+-An Electron Paramagnetic Resonance Study

“…Lines arising from the low-field transitions were not observed experimentally, but this is not surprising in view of the magnitude of the hyperfind coupling parameters. 3 Schawlow, Hume, and Crawford 4 have calculated a value of 2.60 em-I for the isotropic hyperfine coupling of a 6s electron with the 207Pb nucleus. On this basis, our experimental isotropic splitting of 0.293 cm-1 results in an assignment of 11.3% 6s character to the orbital containing the odd electron.…”