Oxo-sulfidobis(dithiolene)tungsten(VI) complexes were prepared in situ by the reaction of oxobis(dithiolene)tungsten(V) precursors with hydrosulfide (SH-). The complexes, characterized by UV-vis, electrospray ionization mass spectrometry, IR, and resonance Raman spectroscopies, model the proposed coordination environment and observed hydrolytic reactions of members of the aldehyde ferredoxin oxidoreductase family of tungsten enzymes.