unsaturated organosilicon compounds s of the general formula 1 h 2 c u2550 c r 1 c o o w o x u2014 r 2 y u2014 si r 3 z or 4 3 z 1 r 1 is a hydrogen atom or a linear or branched hydrocarbon radical having 1 10 carbon atoms r 2 is a linear or branched hydrocarbon radical which has 1 40 carbon atoms and may contain one or more heteroatoms selected from among the elements nitrogen oxygen sulfur and phosphorus r 3 and r 4 are linear or branched hydrocarbon radicals having 1 10 carbon atoms w can be 0 or 1 x can be 0 or 1 y can be 0 or 1 and z can be 0 1 or 2 where w and x must not at the same time be 1 wherein at least one step of the preparation or handling is carried out in an industrial apparatus a whose surfaces which come into contact with the organosilicon compounds s comprise at least 70 of an iron free material where a material is designated as iron free when it contains less than 1 by weight of iron and the industrial apparatus a is either an apparatus for a batch process having a fill volume of at least 200 l or an apparatus for a continuous process having a throughput of at least 15 l h when iron free materials are used the polymerization of organosilicon compounds s is greatly slowed or completely prevented during the preparation or handling thereof the method prevents polymerization in all preparative or handling steps such as synthesis purification such as.