The Molecular Structure of Nickel Carbonyl

Abstract

Electron diffraction by the vapor of Ni(CO)₄ leads to a molecular model in which the four carbonyl groups have a tetrahedral arrangement about the nickel atom with the distances Ni – C = 1.82±0.03A and C – O = 1.15A. These distances are compatible with resonance between two electronic structures in which the C – O bond resonates between triple and double electron pair bonds and the Ni – C bond between single and double electron pair bonds. Nickel carbonyl is the first quadricovalent compound of neutral nickel whose structure has been determined, and its tetrahedral configuration is contrasted with the square arrangement of bonds in the quadricovalent compounds of divalent nickel ion.