Synthesis. The samples of about 1g each were prepared by arc melting from pure elements (all Alfa Aesar) -Ln pieces (99.9 %), Ni pieces (99.99 %) and Si grains (99.999 %). The melting was performed in an arc furnace with a thoriated tungsten electrode, on a copper hearth and under a zirconium-gettered argon atmosphere. The initial ingots were remelted at least three times after turning them upside-down to ensure good homogenization. The as-cast samples were wrapped in Mo outgassed foil, closed in evacuated fused silica tubes and annealed at 1000° C for 7 days. Finally, the samples were quenched in cold water. Mass losses did not exceed 0.7%. software package (Bruker AXS, 2015), while the frames were integrated with the Bruker SAINT program using a narrow-frame algorithm for the integration of the data; absorption effects were corrected using the multi-scan method (SADABS). Initial models of the crystal structures were obtained with the program SHELXT-2018 and refined using the program SHELXL-2018 37 within the APEX3 software package. The atomic displacement parameters were refined anisotropically for all atoms. Crystallographic data and details of the crystal structure refinements have been collected