A mercury-dispensing device is disclosed that includes a mercury dispenser comprising an intermetallic compound including mercury and a second metal selected from the group consisting of titanium, zirconium, and mixtures thereof; and a promoter that comprises copper, tin and at least a third metal selected among the rare earth elements. A getter material selected among titanium, zirconium, tantalum, niobium, vanadium and mixtures thereof, and alloys of these metals with nickel, iron or aluminum can be included in the device. The mercury dispenser, promoter and optional getter material are provided preferably in the form of powders compressed as a pellet, or contained in a ring-shaped metallic support or rolled on the surfaces of a metallic strip. Also disclosed is a process for introducing mercury into electron tubes by making use of the above-mentioned mercury-dispensing devices.