Negative thermal ion mass spectrometry of osmium, rhenium and iridium

We report on a technique for obtaining intense ion beams of negatively charged oxides of Os, Re and Ir by thermal ionization, in a conventional surface ionization mass spectrometer. It was found that the principal ion species of Os, Re and Ir produced are OsO3−, ReO4− and IrO2−. The sharp distinction in the masses of the dominant molecular species produced by this technique permits the measurement of isotopic compositions of each element from...