AbstractHigh polymers with a regular chain structure have been produced by polymerization of ethylene with complexes containing crystalline organolithium compounds and titanium tetrachloride in organic solvents. For this purpose RLi compounds have been prepared, R being methyl, ethyl, butryl, dodeeyl, tolyl, mesityl, naphthyl, benzyl, and other aliphatic and aromatic groups. The investigation of the polymerization has led to the elucidation of the influence of the nature of the organic radical bound with lithium on the properties of polythene formed. Thermomechanical data, infrared and X‐ray spectra, as well as viscometric molecular weight determination, have shown all specimens of polyethylene to be highly crystalline and of a regular chain structure. The polymers obtained have mechanical properties characteristic of polyethylenes of this type but with elongations that strongly differ in polymers produced using organolithium complexes with different radicals at the lithium. With some specimen, elongation has been found to reach extremely high values. Some suggestions have been made as to the causes of influence of different organic radicals in RLi on the properties of polymer