**Number of M-M Bonds in Cp(CO)Fe(u-CO)2Fe(CO)Cp**

To determine the number of M-M bonds in the given compound Cp(CO)Fe(u-CO)2Fe(CO)Cp, we need to analyze the molecular structure and electron arrangement around the metal atoms.

**Molecular Structure**

The compound consists of two Cp(CO)Fe units connected by a bridging carbonyl (u-CO) ligand. Each Cp(CO)Fe unit contains a cyclopentadienyl (Cp) ligand and two carbonyl (CO) ligands. The metal atom in each Cp(CO)Fe unit is iron (Fe).

**Analysis**

1. Cp(CO)Fe Unit:
- The Cp ligand is a cyclic ligand with a delocalized pi system. It acts as a 5-electron donor.
- Each CO ligand is a sigma donor, providing two electrons to the metal atom.
- The Fe atom has a valence electron configuration of [Ar] 3d6 4s2.
- Considering the Cp ligand and two CO ligands, the Fe atom has a total of 9 valence electrons available for bonding.

2. Bridging Carbonyl (u-CO) Ligand:
- The bridging carbonyl ligand connects the two Cp(CO)Fe units.
- It acts as a sigma donor, providing two electrons to each Fe atom.

3. Fe-Fe Bonding:
- The bridging carbonyl ligand forms a direct bond between the two Fe atoms.
- This bond is a coordination bond, involving the donation of two electrons from each Fe atom to the bridging carbonyl ligand.

**Conclusion**

Based on the analysis, there are no M-M bonds in the compound Cp(CO)Fe(u-CO)2Fe(CO)Cp. The bridging carbonyl ligand connects the two Fe atoms but does not result in the formation of a direct metal-metal bond. Therefore, the correct answer is '0'.