Valence shell electron-pair repulsion multiple bonds

Tetranuclear monoadducts with asymmetrical M- O M bridges related to those of [M2OCI9] have been characterized but most structural data concern monomeric NbOCls bis adducts. In such derivatives, the metal is octahedrally surrounded with the neutral Ugands cis to each other, one being trans to the 0x0 bond, which is short (typical Nb=0 Bond Length 1.70 A). The coordination polyhedron is distorted as a result of the niobium-oxygen multiple bond (see Valence Shell Electron Pair Repulsion Model). ... 

Lewis theory, in combination with valence shell electron pair repulsion (VSEPR) theory, can be used to predict the shapes of molecules. VSEPR theory is based on the idea that electron groups—lone pairs, single bonds, or multiple bonds—repel each other. This repulsion between the negative charges of electron groups on the central atom determines the geometry of the molecule. For example, consider CO2, which has the Lewis structure ... 

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