We report Ni isotope ratio results for Ni from metal in iron meteorites and from metal and olivine in pallasites. The investigation of pallasites was undertaken because (1) previous work on pallasites showed evidence for in situ decay of Mn (t1⁄2 = 3.7 Ma) in olivines [1,2] and of Pd (t1⁄2 =6.5 Ma) in metal [3]; (2) evidence for the in situ decay of Fe (t1⁄2 = 1.5 Ma) in eucrites [4,5]; (3) pos...

Multiple chondritic meteorite fragments have been found in two sedimentary rock samples from an end-Permian bed at Graphite Peak in Antarctica. The Ni/Fe, Co/Ni, and P/Fe ratios in metal grains; the Fe/Mg and Mn/Fe ratios in olivine and pyroxene; and the chemistry of Fe-, Ni-, P-, and S-bearing oxide in the meteorite fragments are typical of CM-type chondritic meteorites. In one sample, the met...

Introduction: The evidence for the presence of short-lived Fe (decaying into Ni, with the half life of 1.5 Ma) in the early system has recently received considerable attention, both experimentally and theoretically. Evidence for Ni excesses in eucrites, without correlation to Fe/Ni has been obtained by Shukolyukov and Lugmair [1, 2]. Recently, based on ion microprobe studies of phases with very...

Nanoscale bimetallic Ni/Fe particles were synthesized from the reaction of sodium borohydride (NaBH4) with reduction of Ni2+ and Fe2+ in aqueous solution. The obtained Ni/Fe particles were characterized by TEM (transmission electron microscope), XRD (X-ray diffractometer), and N2-BET. The dechlorination activity of the Ni/Fe was investigated using p-chlorophenol (p-CP) as a probe agent. Results...

Introduction: One of the most debated subjects in meteoritics is the time scale of events that occurred during the early history of the solar system. Chronometers based on short lived nuclides, such as Al, Mn, Fe, Pd, I, Sm, were extensively studied during the last decades. Some of them were shown to afford chronological resolutions on the order of a few Ma to less than one Ma [e.g. 1,2]. This ...

A crystal structure of the anaerobic Ni-Fe-S carbon monoxide dehydrogenase (CODH) from Rhodospirillum rubrum has been determined to 2.8-A resolution. The CODH family, for which the R. rubrum enzyme is the prototype, catalyzes the biological oxidation of CO at an unusual Ni-Fe-S cluster called the C-cluster. The Ni-Fe-S C-cluster contains a mononuclear site and a four-metal cubane. Surprisingly,...

Treatment of [NEt4][(pzTp)Fe(III)(CN)3] (1) with Ni(II)(OTf)2 (OTf = trifluoromethanesulfonate) and 1,5,8,12-tetraazadodecane (L) affords {[(pzTp)Fe(III)(CN)3]2[Ni(II)L]} x 1/2MeOH (2), while 2,2'-bipyridine (bipy) affords {[(pzTp)Fe(III)(CN)3]2[Ni(II)(bipy)2]} x 2 H2O (3). Magnetic measurements indicate that 2 and 3 have S = 2 ground states and that 3 exhibits slow relaxation of the magnetizat...

The divalent transition-metal cations Fe, Co, and Ni were used to test the hypothesis that Mn ions pass through calcium channels because Mn ions have a relatively low energy of hydration. The test ions were applied to the bath and comparisons were made of their effects on Ca or Mn spikes elicited from myoepithelial cells of the proventriculus of the polychaete worm Syllis spongiphila. Control e...