Crosslinkable organosilicon compositions with controllable modulus can be prepared using organosilicon compounds composed of units of the formula (HO).sub.aR.sub.bSiO.sub.(4-a-b)/2 (I), where R is identical or different and is a monovalent, optionally substituted hydrocarbon radical optionally interrupted by heteroatoms, a is 0 or 1, and b is 0, 1, 2 or 3, with the proviso that the organosilicon compound has a single unit of the formula (I) where a=1, and has a viscosity of from 5 to 1000 mPas at 25.degree. C.