The present invention relates to a process for preparing chlorinated oligosilanes, wherein chlorinated polysilane having an empirical formula of SiCl.sub.1.0-2.8 and/or a mixture comprising the chlorinated polysilane is reacted with elemental chlorine or a chlorine-containing mixture. Additionally claimed are chlorinated oligosilanes prepared by the process and the use thereof for production of semiconductors and/or hard coatings.

Provided is a method for stably conducting a process for producing chlorosilanes by a chlorination reaction of metallic silicon. When producing chlorosilanes by the chlorination reaction of the metallic silicon, metallic silicon having a sodium content of 1 ppm or more and 90 ppm or less in terms of element and an aluminum content of 1000 ppm or more and 4000 ppm or less in terms of element is used as the metallic silicon. An average particle diameter of the metallic silicon is preferably about 150 μm to 400 μm.

A method is useful for preparing partially hydrogenated chlorosilanes by selective hydrogenation with a compound of the formula R.sub.2AlH, wherein R is a branched or cyclic hydrocarbon. Partially hydrogenated chlorosilanes can be prepared with said method, in particular partially hydrogenated chlorosilanes represented by the formula Cl.sub.3SiSi(SiH.sub.3).sub.3, (Cl.sub.3Si).sub.2Si(SiH.sub.3).sub.2 or HSi(SiH.sub.3).sub.2SiCl.sub.3.

A method is useful for preparing partially hydrogenated chlorosilanes by selective hydrogenation with a compound of the formula R.sub.2AlH, wherein R is a branched or cyclic hydrocarbon. Partially hydrogenated chlorosilanes can be prepared with said method, in particular partially hydrogenated chlorosilanes represented by the formula Cl.sub.3SiSi(SiH.sub.3).sub.3, (Cl.sub.3Si).sub.2Si(SiH.sub.3).sub.2 or HSi(SiH.sub.3).sub.2SiCl.sub.3.

Provided is a method for stably conducting a process for producing chlorosilanes by a chlorination reaction of metallic silicon. When producing chlorosilanes by the chlorination reaction of the metallic silicon, metallic silicon having a sodium content of 1 ppm or more and 90 ppm or less in terms of element and an aluminum content of 1000 ppm or more and 4000 ppm or less in terms of element is used as the metallic silicon. An average particle diameter of the metallic silicon is preferably about 150 m to 400 m.