| http://www.w3.org/ns/prov#value | - The organometallic compound or compounds of a metal of groups II and III of the periodic table preferably comprise organoaluminium compounds having the mean formula AIR'x Z.sub.(3-x) wherein R' represents an alkyl group containing from 1 to 16 carbon atoms and preferably from 2 to 12 carbon atoms, Z is a hydrogen atom or a halogen such as chlorine or bromine and x is an integer or a fraction which
|
