The present invention relates to crosslinkable compositions are described, containing (1) organosilicon compounds which have radicals containing aliphatic carbon-carbon multiple bonds, and (2) organosilicon compounds having Si-bonded hydrogen atoms, or (3) organosilicon compounds where radicals with aliphatic carbon-carbon multiple bonds and Si-bonded hydrogen atoms are present in the same compound, (4) catalysts which promote the addition of Si-bonded hydrogen onto aliphatic multiple bond, and (5) agents which retard the addition of Si-bonded hydrogen onto aliphatic multiple bond at room temperature, of the formula ##STR1## in which R.sup.1, R.sup.2, R.sup.4, R.sup.5 and R.sup.6 are identical or different and are a hydrogen atom or a monovalent, substituted or unsubstituted hydrocarbon radical having 1 to 12 carbon atoms per radical,R.sup.3 is a divalent hydrocarbon radical having 1 to 6 carbon atoms per radical, X is a radical of the formula --OH, --Cl, Br and --CN, and x and y are identical or different and are 0 or 1, with the proviso that there is at least one double bond.