AbstractMetalloid cluster compounds of tin of the general formulae Sn_nR_m with n>m (R=organic ligand), where beside ligand-bound tin atoms also “naked” tin atoms, that only bind to other tin atoms, are present, represent a novel class of cluster compounds in tin chemistry. As the “naked” tin atoms inside these clusters exhibit an oxidation state of 0, the average oxidation state of the tin atoms within such metalloid tin clusters is in between 0 and 1. Thus, these cluster compounds may be seen as intermediates on the way to the elemental state. Therefore, interesting properties are expected for these compounds, which might complement results from nanotechnology. During the last years, different syntheses of such novel cluster compounds have been introduced, leading to several metalloid tin cluster compounds, which exhibit new and partly unusual structure and bonding properties. In this review, recent results in this novel field of group 14 chemistry are discussed, whereby special attention is focused on the novel synthetic route applying a disproportionation reaction of metastable Sn(I) halides.