Structures of Homoleptic Metal Carbonyls

Structures & Metal-Metal Bonds:

$$\text{Ni}(\text{CO})_4 \implies \text{Tetrahedral } (sp^3, \text{ Diamagnetic})$$

$$\text{Fe}(\text{CO})_5 \implies \text{Trigonal Bipyramidal } (dsp^3, \text{ Diamagnetic})$$

$$\text{Cr}(\text{CO})_6 \implies \text{Octahedral } (d^2sp^3, \text{ Diamagnetic})$$

$$\text{Mn}_2(\text{CO})_{10} \implies 1 \text{ Metal-Metal (Mn--Mn) bond, 0 Bridging CO ligands}$$

$$\text{Co}_2(\text{CO})_8 \implies 1 \text{ Metal-Metal (Co--Co) bond, 2 Bridging CO ligands}$$

Concept:

Polynuclear metal carbonyls achieve stable 18-electron configurations through metal-metal ($$\text{M--M}$$) single bonds and bridging $$\text{CO}$$ ligands.

Notation:

• Bridging $$\text{CO}$$ = Carbonyl ligand shared simultaneously between two central metal atoms.