Molecular lattice fragment of LiI. Crystal structure and ab initio calculations of [LiI(NEt3)]4.

Numerous crystal structures of donor-stabilized LiX species are known, but only two of them show a heterocubane arrangement [LiX(Do)]4 (X = Cl, Br; Do = donor) in the solid state. Herein we report the X-ray crystal structure of [LiI(NEt3)]4 (1), obtained by the reaction of LiN(SiMe3)2 with either GaI or All in the presence of NEt3. The structural backbone of 1 is a [LiI]4 heterocubane core, which is compared to [LiX]4 (X = Cl, Br) as well as to [Li(CH3)]4. The energetics of the formation of 1 and its stability with respect to solid LiI is rationalized and additionally supported by DFT (density functional theory) calculations.