Аннотация:The crystal structure of decakis(μ-chloro)-tetrakis(1,2,4-triphenylcyclopentadienyl)-hexakis(tetrahydrofuran)-di-potassium-tetra-neodymium(III) tetrahydrofuran trisolvate, 1, is reported. The centrosymmetric complex 1 has a raretetranuclear core [Ln4K2Cl10] and crystalizes in triclinic space group (P̄ ) with unit cell parameters: a = 11.9858(3) Å,b = 14.0698(3) Å, c = 19.8129(4) Å, α = 74.1120(4)°, β = 81.2073(4)°, γ = 83.9521(4)° and Z = 1 The catalytic system basedon 1 and nBuMg(O-2,6-tBu2-4-MeC6H2) exhibits moderate activity in coordinative chain transfer polymerization of ethylene.In case of the system 1/nBu2Mg, oligomerisation of ethylene was not detected.