Transition-metal catalysis coordination number, geometry

Indeed, the application of transition-metal catalysis in organic synthesis is built around many such formalisms. In addition to the formal oxidation state, these include coordinative unsaturation, coordination number, and coordination geometry, hydride formalism and the 18-electron and 16-18-electron rules, also referred to as electron bookkeeping. 

Eormalisms in transition metal catalysis Uniqueness of transition metals Oxidation state of a metal Coordinative unsaturation, coordination number, and coordination geometry Ligands and their roie in transition metal catalysis... 

The most common coordination numbers for transition metal complexes of relevance in catalysis are four, five, and six. However, a few metal complexes with coordination numbers two, three, and seven are also of relevance. Structures 2.3-2.8 show the common coordination geometries for coordination numbers four, five, and six. 

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