TcO 4– is reduced by thiourea /tu/ to Tc/III/ in 6N HCl. By capillar electrophoresis three different cations have been identified with electrophoretic mobilities of u=/4.3–4.8/x10–4 u=/3.2–3.8/x10–4, and u=/2.2–2.8/x10–4 cm2 v–1s–1. These species were assigned to complex cations [Tc/tu/6]3+, [Tc/tu/5Cl]2+, and [Tc/tu/4Cl2]+, respectively. [Tc/tu/6]3+ was identified by spectrophotometry according to recently published data. [Tc/tu/5Cl]2+ was isolated and chemically characterized. The formation of the monovalent cation [Tc/tu/5Cl2]+ was concluded from spectrophotometrical measurements.