On the equilibrium between thallium(II) hydroxide and hydroxothallium(II) ion: a pulse-radiolysis study

Abstract

The oxidation of Tl⁺ by OH˙ radicals leads to an addition product [Tl(OH)]⁺ which exists in the equilibria [Tl(OH)]⁺⇌ Tl²⁺+[OH]^– and Tl[OH]₂⇌[Tl(OH)]⁺+[OH]^–. The previously unrecorded pK of the latter equilibrium has been determined as 7.7 ± 0.2. The optical-absorption spectrum of Tl[OH]₂ shows a maximum at 370 nm (ε 3.8 × 10³ dm³ mol^–1 cm^–1) and a band rising towards the u.v. below 300 nm. Thallium(II) hydroxide, in contrast to Tl²⁺ and [Tl(OH)]⁺, does not exhibit good oxidizing properties. It may even transfer an electron to suitable acceptors such as tetrantromethane.