Two novel mixed metal rhodium-platinum clusters have been synthesized by the reaction of [Rh₄(CO)₁₂] with [Pt(PPh₃)₃]. The structure of [Rh₂Pt₃(μ-CO)₅(CO)₄(PPh ₃)₃] 1 has been established by a single crystal X-ray diffraction study. The tetranuclear cluster [Rh₂Pt₂(μ-CO)₃(CO)₄(PPh ₃)₃] 2 has been characterised by FAB mass spectrometry and shown by various multinuclear NMR techniques (¹³C, ³¹P, {³¹P-³¹P} COSY and {¹³C-¹⁰³Rh} and {³¹P-¹⁰³Rh} heteronuclear multiple quantum coherence, HMQC) to adopt a butterfly type structure. The carbonyl migration pathways in 2 have been established by a combination of EXSY and 1-D variable temperature measurements; independent localised exchange about the hinge rhodium atoms and interchange of bridging and semi-bridging carbonyls on the Pt-Rh bonds occur.