Anhydrous LnCl3 were purchased from Alfa Aesar and were used as received. 2.2.2-cryptand was purchased from Alfa Aesar, dissolved in THF and dried over molecular sieves; this solution was transferred from the sieves and THF was removed in vacuo before use. [Ln(Cp tt )3] (Ln = La, Ce, Nd, Sm), KC8, KCp tt , and [NdI3(THF)4] were prepared according to literature methods. absorption correction with a beam profile was applied. The structures were solved using SHELXT; the datasets were refined by full-matrix least-squares on all unique F 2 values, with anisotropic displacement parameters for all non-hydrogen atoms, and with constrained riding hydrogen geometries; Uiso(H) was set at 1.2 (1.5 for methyl groups) times Ueq of the parent atom. The largest features in final difference syntheses were close to heavy atoms and were of no chemical significance.