Gas phase chemistry of technetium and rhenium oxychlorides

The chloride and oxychloride chemistry of the group 7 elements Tc and Re wa s investigated in order to develop an experimental approach to a gas chemic al characterisation of bohrium (Bh, element 107). In thermochromatography e xperiments with trace amounts of (TC)-T-101.104 and Re-183.184 the formatio n of one volatile compound was observed in O-2/HCl containing carrier gas, which was attributed to MO3Cl (M = Tc, Re). From the measured deposition te mperatures the adsorption enthalpies on quartz surfaces Delta H-ads(TcO3Cl) = -51 +/- 3 kJ/mol and Delta H-ads(ReO3Cl) = -62 +/- 3 kJ/mol were evaluat ed. The sublimation enthalpies were derived using an empirical correlation between Delta H-ads and Delta H-subl: Delta H-subl(TcO3Cl) = 49 +/- 10 kJ/m ol and Delta H-subl(ReO3Cl) = 67 +/- 10 kJ/mol. A fast gas chemical separat ion technique for highly volatile compounds of short-lived isotopes based o n isothermal gas solid adsorption chromatography (OLGA-principle) was devel oped. With a modified OLGA device, model studies with the short-lived nucli des (TC)-T-106.107,108 and Re-169,Re-170,Re-174,Re-176 were carried out in preparation of an experimental gas chemical investigation of bohrium (Bh, e lement 107). Separation times of less than 3 s were achieved. A good separa tion of the oxychlorides of group 7 elements from chloride and oxychloride compounds of Er152-155, 151-154HO (as models for actinide elements), Nb98-1 01, Zr99-102, Zr99-102 (as models for Light transactinide elements), Po-218 , and Bi-214 was accomplished in this chemical system.