The reaction of stanna- closo-dodecaborate [SnB 11H 11] (2-) (1) with CdBr 2 gave the tetrahedrally coordinated compound [Cd(SnB 11H 11) 4] (6-)(2). The same coordination mode can be found in [Hg(SnB 11H 11) 4] (6-) (3), which was obtained by reaction of stannaborate with Hg 2Cl2. Both compounds were characterized by single crystal X-ray analysis and heteronuclear NMR techniques.