C 10 H 26 B 20 Se 4 , monoclinic, P12 1 /n1 (no. 14), a = 10.3649(4) Å, b = 13.8582(7) Å, c = 18.3667(8) Source of materialIn an NMR tube, tropylium bromide (0.15 g, 0.88 mmol) was added to a solution of 1,2-bis(trimethylsilylseleno)-1,2-dicarbacloso-dodecaborane(12) (0.1 g, 0.224 mmol) in 1.0 mL of deutered benzene, a yellow solution was observed and analyzed by NMR spectroscopy. After one month, the formation of yellow crystals was observed, the crystals were isolated and analyzed by X-ray diffraction (yield 0.012 g, 12 %). DiscussionRecently, we described the molecular structures of cyclic compounds of tellurium