One-pot oxidation and protonation of the sulfide bridging complex [Pt(2)(micro-S)(2)(PPh(3))(4)] can be promoted by lanthanide or scandium compounds, leading to the isolation of [Pt(2)(micro-S(2)O(2)H)(PPh(3))(4)](+); crystallographic elucidation confirmed sulfide mono-oxygenation without S-S bonding to give formally [SO](2-) in the form of an [SOHOS](3-) overhead bridge.