An improved mercury-dispensing combination of materials is made up of a compound A including mercury and a second metal selected among titanium, zirconium and mixtures thereof and an alloy or an intermetallic compound B including copper and tin, said mercury-dispensing combination of materials further containing an amount of oxygen comprised between 0.03% and 0.48% with respect to the overall weight of the composition A+B. It is also possible to add a getter material C that includes metals such as titanium, zirconium, tantalum, niobium, vanadium and mixtures thereof or their alloys with other metals such as nickel, iron, aluminum.