The gas-phase reactivities of the transition-metal sulfides ScS+ and TiS+ are investigated with guided-ion beam (GIB) and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Tn this work, we study the reactions of bare Sc+ and Ti+ ions with sulfur-transfer reagents, COS and CS2, and of the metal sulfides, ScS+ and TiS+, with oxygen-transfer substrates and with Xe to examine their collision-induced dissociation. The GIB experiments lead to several estimates for D-0(M+-S). Further, the reaction MS+ + H2O --> MO+ + H2S and its reverse are studied with GIB and FTICR. The equilibrium constants K-eq derived from these measurements provide the most accurate values for D-0(M+ - S). Overall assessment of the results of ion-molecule reactions, collision-induced dissociations, and equilibrium measurements yields the 0 K bond dissociation energies D-0(Sc+ - S) = 4.97 +/- 0.05 eV, D-0(Ti+ - S) = 4.74 +/- 0.07 eV, D-0(Sc+ - CS) = 1.38 +/- 0.08 eV, D-0(T+ - CS) = 1.60 +/- 0.06 eV, and Delta(f)H(0)(TiOS+) = 9.04 +/- 0.18 eV.