Abstract: In this paper the reaction of Nd metal vapor produced at high temperature below 10^-5 mmHg with bezene at-196℃ to give benzeneneodymium complex has been investi-gated. The chemical composition of the product was identified as (C₆H₆)₃Nd₂ by che-mical analysis. The product is a black needle solid, insoluble in organic solvents, stable at room temperature, extremely sensitive to air and moisture and pyrophoric in air. The complex decomposes by water and alcohol, evolving hydrogen. Combined with Al₂Et₃Cl₃ the complex polymerizes butadiene to polymer with cis-1,4 content of 77.3%, trans-1,4 17.4%, and 1,2 5.3%.