[en] For the first time, a Hs containing compound has been investigated chemically. With the formation of a very volatile tetroxide, Hs behaves as expected and is a typical member of group 8 of the periodic table. (orig.)

[en] The volatility of plutonium oxides in the O₂-H₂O_(g)/SiO_2(s) system has been studied by thermochromatography. The experimental results indicate the oxidation of Pu(IV) to Pu(VI) by moist oxygen. (orig.)

[en] In preparation of experiments to characterize Sg as oxide hydroxide a new High Temperature On-Line Gas Chromatography Apparatus (HITGAS) based on the OLGA design was developed. The time-consuming recluster step was replaced by direct deposition of species leaving the chromatographic column on metal foils. In test experiments with short-lived Mo isotopes a retention time of 9 s was determined for an isothermal temperature of 1270 K, sufficiently short to study Sg isotopes ²⁶⁵Sg and ²⁶⁶Sg. A model based on the theory of supersonic expansion of gases and on simple geometric considerations reproduces the data of direct condensation experiments quite well

[en] Seaborgium (Sg; element 106) was studied in comparison with tungsten in the O₂-H₂O_(g)/SiO_2(s)-system using high temperature on-line isothermal gas chromatography. The 21-s nuclide ²⁶⁶Sg was produced in the ²⁴⁸Cm + ²²Ne reaction at a beam energy of 119 MeV. The reaction products were continuously transported by a He(MoO₃)-jet to the chromatography apparatus HITGAS. Group 6 element oxide hydroxide molecules volatile at temperatures above 1000 K were formed at 1325 K by adding humid oxygen as reactive gas. ²⁶⁶Sg was unambiguously detected after gas chromatographic separation by measuring ²⁶⁶Sg-²⁶²Rf mother-daughter α-sf correlations. The experimental results demonstrate the volatility of Sg in humid oxygen, presumably as Sg oxide hydroxide, a behavior typical for both U(VI) and the group 6 elements. (orig.)

[en] The simulation of thermochromatographic processes by the Monte Carlo method has been extended to reaction gas chromatography, governed by the surface reactions dissociative adsorption and associative desorption. The method has been applied to thermochromatographic surface reaction studies with oxide and hydroxide species of molybdenum in open tubular quartz columns. Positions and shapes of thermochromatographic zones were calculated in dependence of reaction type, humidity of the carrier gas, and exposure time and compared to experimental results. (orig.)

[en] The transport of Mo through quartz tubes with dry and moist oxygen in the temperature range 330 - 1480 K was studied by thermochromatography. Thermochromatographic deposition temperatures were determined in dependence on the amount of Mo, the humidity of the carrier gas, and the exposure time. In dry oxygen the transport of macroamounts is governed by the process (MoO₃)_n(g) <=> n MoO_3(s). In moist oxygen the deposition temperature was nearly constant up to a water vapour pressure of 2.3 kPa. The deposition of carrier-free isotopes of Mo varied significantly with the humidity of the carrier gas. The transport can be described by MoO_3(g) <=> MoO_3(ads) for dry oxygen and MoO₂(OH)_2(g) <=> MoO_3(ads) + H₂O_(g) for moist oxygen. Thermodynamic functions were determined for simple adsorption processes and complex dissociative adsorption reactions. (orig.)

No abstract available

[en] Trace amounts of oxidic plutonium species were studied by thermochromatography in silica glass columns in comparison to oxidic species of Th, Pa, U, Np, and Am. Humid oxygen was used as reactive admixture to the carrier gas helium. The thermochromatographic behavior of plutonium provides evidence for the oxidation of Pu(IV) to Pu(VI) with humid oxygen. The gas chromatographic transport of U, Np, and Pu is governed by the surface reaction MO₂(OH)_2(g) ↔ MO_3(ads) + H₂O_(g), with M = U, Np, and Pu in the hexavalent state and competitive reactions of the actinide oxides with silica to nonvolatile compounds or solid solutions. There is good agreement with earlier volatility studies and the reported oxidation of PuO₂ with water. The oxidation to PuO₄ as claimed by Domanov could not be confirmed. (orig.)

[en] The adsorption/desorption behavior of carrier-free W on quartz-glass 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. (orig.)

No abstract available