Gas Chromatographic Studies of Oxide and Hydroxide Species of Tungsten - Model Experiments with Respect to the Physico-Chemical Characterization of Seaborgium (Element 106)

Abstract

The adsorption/desorption behavior of carrier-free W on quartzglass surfaces in dry and moist oxygen was studied by off-line thermochromatography in the temperature range 330-1480 K. In dry oxygen W could not be volatilized. In moist oxygen the deposition temperature varies significantly with the humidity of the carrier-gas. The transport can be described by WO₂(OH)_2(g) ⇆ WO_3(ads) + H₂O_(g) analogous to the lighter homologue Mo. Evaluation of the experimental data was carried out by means of the new computer code TECPROF which allows to consider real temperature profiles. Up to an admixture of 60 μg MoO₃-carrier the formation of heteropolynuclear complexes was not observed. However, the W was deposited at higher temperatures compared to experiments without a homologous carrier. Isothermal on-line gas chromatography experiments were carried out with short-lived W isotopes to model future Sg experiments and to optimize the experimental conditions.