Rotatory dispersion in hydrated cobaltous salts

Chemical shifts are recorded for the thallium resonance of ²⁰³Tl and ²⁰⁵Tl in a number of thallium compounds in the solid state and in aqueous solutions. Different chemical shifts are found for Tl⁺, TlCl₄′ and TlCl₆…'. Solid Tl₂Cl₃ shows two thallium resonances with intensities in the ratio 3 : 1, consistent with the formula Tl₃(TlCl₆). Hydrated thallic chloride in the solid state shows three thallium resonances which may be due to the presence of Tl(H₂O) _x ⁺⁺⁺, TlCl₄′ and TlCl₆…'. The chemical shifts of the thallium resonance in aqueous thallic chloride and bromide solutions in the presence of added halides are consistent with the stepwise formation of complex ions. The second moments of the resonances of the two thallium isotopes in solid compounds shows that there is spin-spin coupling between the thallium isotopes, and a weak coupling in some cases between thallium nuclei and the nuclei of anions.