A mercury-dispensing combination suitable to release an amount of mercury higher than 60% during the activation step, even after partial oxidation, includes a mercury-dispensing intermetallic compound A with Hg and a second metal selected among Ti, Zr and mixtures thereof, as well as a promoting alloy or intermetallic compound B including Cu and a second metal selected among Sn, In or Ag or combinations thereof. There is also disclosed a mercury-dispensing device containing a combination of materials A and B, in addition to a process for introducing mercury into electron tubes consisting in the introduction of one of said devices inside the open tube and then heating thereof at a temperature between 550.degree. and 900.degree. C. after the tube sealing in order to get Hg free.