(Chemical Equation Presented) The reduction of SnCl2 by the low-valent gallium(I) β-diketiminate GaI(ddp) gives the title complex, which is best described as a Zintl-type anionic [Sn17] 4- cluster stabilized by an electrophilic shell of gallium ligands. This reaction could represent a new concept for the synthesis of metalloid main-group clusters. ddp = HC(CMeNC6H3-2,6-iPr 2)2. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.