Dissolution of X-ray irradiated sodium chloride or additively coloured potassium chloride induces generation of hydrated electrons which produce thallium(I)-specific chemiluminescence in the presence of thallium(I) ions. Such a luminescence is also called extrinsic lyoluminescence (ELL) of X-ray irradiation coloured sodium chloride, or additively coloured potassium chloride. The present ELL is considered chemiluminescence induced by dissolution-produced strong reducing and oxidising agents, i.e. hydrated electrons, surface-bound and only partially hydrated hole centres, and hydroxyl or sulphate radicals (in the case of additively coloured potassium chloride dissolved in solution containing peroxodisulphate ions). Dichlorothallate(I) (Tl(I)Cl - 2 ) was the main emitter in the ELL processes at about 430nm. The reduction-initiated excitation pathway of TlCl - 2 involves a colloidal thallium atom surrounded by chloride anions (Tl(O):2Cl - ) while in the less important oxidation-initiated excitation pathway the precursor of excited Tl(I)Cl - 2 is transiently existing Tl(II)Cl - 2 produced by dissolution-uncovered hole centres (or sulphate radicals). Both of the lyoluminescence procedures allow Tl(I) to be detected below nanomolar concentrations, yielding linear log-log calibration plots spanning several orders of magnitude of concentration.