[Tc(OH(2))(CO)(3)(PPh(3))(2)](BF(4)) has been used as a synthon for reactions with small inorganic ligands with relevance for the treatment of nuclear waste solutions such as nitrate, nitrite, pseudohalides, permetalates (M = Mn, Tc, Re), and BH(4)(-). The formation of bond isomers and/or a distinct reactivity has been observed for most of the products. [Tc(NCO)(CO)(3)(PPh(3))(2)], [Tc(NCS)(CO)(3)(PPh(3))(2)], [Tc(CN)(CO)(3)(PPh(3))(2)], [Tc(N(3))(CO)(3)(PPh(3))(2)], [Tc(NCO)(OH(2))(CO)(2)(PPh(3))(2)], [Tc(eta(2)-OON)(CO)(2)(PPh(3))(2)], [Tc(eta(1)-NO(2))(CO)(3)(PPh(3))(2)], [Tc(eta(2)-OONO)(CO)(2)(PPh(3))(2)], [Tc(eta(1)-ONO(2))(CO)(3)(PPh(3))(2)], [Tc(eta(2)-OO(CCH(3)))(CO)(2)(PPh(3))(2)], [Tc(eta(2)-SSC(SCH(3)))(CO)(2)(PPh(3))(2)], [Tc(eta(2)-SSC(OCH(3)))(CO)(2)(PPh(3))(2)], [Tc(eta(2)-SSC(CH(3)))(CO)(2)(PPh(3))(2)], [Tc(eta(2)-SS(CH))(CO)(2)(PPh(3))(2)], [Tc(OTcO(3))(acetone)(CO)(2)(PPh(3))(2)], [Tc(OTcO(3))(CO)(3)(PPh(3))(2)], and [Tc(eta(2)-HHBH(2))(CO)(2)(PPh(3))(2)] have been isolated in crystalline form and studied by X-ray crystallography. Additionally, the typical reactivity patterns (isomerization, thermal decomposition, hydrolysis, or decarbonylation) of the products have been studied by spectroscopic methods. (99)Tc NMR spectroscopy has proved to be a particularly useful tool for the evaluation of such reactions of the diamagnetic technetium(I) compounds in solution.