Stibinidene complexes are rare and highly sensitive low-valent main group compounds, which have not been studied extensively for their reaction behavior so far. In the reaction with GaCl3, the stibinidene complex [ClSb{Cr(CO)(5)}(2)(thf)] (1) shows a dimerization to [ClSb{Cr(CO)(5)}(2)](2) (2) and yields the anionic double-chlorinated compound [Cl2Sb{Cr(CO)(5)}(2)](-) (3) in the reaction with different ionic nucleophiles. When using neutral nucleophiles (such as amines, isocyanides and phosphines) as reaction partners, tetrahedral complexes of the type [ClSb{Cr(CO)(5)}(2)Nu] (4: Nu=NH(2)Mes; 5: Nu=CN(dmp); 6: Nu=PPh3; 7: Nu=PPh2H) are formed which can be used in subsequent reactions. All of these products are among the first of their type to be synthesized and isolated.