[Mn2(CO)10] is a polynuclear metal carbonyl compound. It is decarboxyldimanganese (0) which is made up of two square pyramidal Mn(CO)5 units joined by a Mn-Mn bond. The structure of [Mn2(CO)10] is
Here, no CO ligand is a bridging ligand. So, number of bridging CO ligands in [Mn2(CO)10] is 0 (zero).