Patrick K. Ng

The line broadening and contact shift studies of some metal ion-DMSO complexes

Abstract Contact shift and line broadening studies were made on a series of metal ion-dimethylsulfoxide (DMSO) solutions. Unpaired spin density transfer for Cu(DMSO)62+ and Ni (DMSO)62+ complexes is through the σ bonding system while the signs of the electron spin-nuclear spin coupling constants, An, for Co(DMSO)62+, Fe(DMSO)62+ indicate a ligand π-to-metal t2g unpaired spin density transfer. Line broadening studies reveal that Co(DMSO)62+ and Mn(DMSO)62+ exchange too fast in DMSO solution to be measured by the NMR technique while Fe(DMSO)63+ and Cr(DMSO)63+ exchange too slowly to be measured. The exchange rate and the ΔH‡ and ΔS‡ of exchange were determined for Cu(DMSO)62+, Ni(DMSO)62+ and Fe(DMSO)62+. The exchange rate order was found to be Fe > Cu > Ni.

Distribution of Nickel Hydroxide in Sintered Nickel Plaques Measured by Radiotracer Method during Electroimpregnation

Sintered nickel positive electrodes were prepared by electroimpregnating nickel hydroxide inside a porous nickel plaque in a nickel nitrate solution. The distribution of nickel hydroxide inside the plaque was measured using a radio-tracer method with /sup 63/Ni as the radioactivity source. Autoradiography and ..beta.. counting were used to follow qualitative and quantitative distributions, respectively, of the pore filling process. Relatively uniform distribution was observed at low current density, and the precipitation of Ni(OH)/sub 2/ extends to the center of the plaque. At high current density, most of the Ni(OH)/sub 2/ aggregated in the region just underneath the plaque surface, causing a somewhat nonuniform distribution. Nickel hydroxide also precipitates heavily on the surface of the plaque at high current density, reducing the penetration of electrolyte to the inside of the plaque.