Quadruple bond

A quadruple bond is a type of chemical bond between two atoms involving eight electrons. This bond is an extension of the more familiar types of covalent bonds: double bonds and triple bonds.[1] Stable quadruple bonds are most common among the transition metals in the middle of the d-block, such as rhenium, tungsten, technetium, molybdenum and chromium. Typically the ligands that support quadruple bonds are π-donors, not π-acceptors. Quadruple bonds are rare as compared to double bonds and triple bonds, but hundreds of compounds with such bonds have been prepared.[2]

The structure of chromium(II) acetate contains a quadruple Cr–Cr bond.
  1. ^ Radius, U.; Breher, F. (2006). "'To Boldly Pass the Metal–Metal Quadruple Bond". Angew. Chem. Int. Ed. 45 (19): 3006–3010. doi:10.1002/anie.200504322. PMID 16642513.
  2. ^ Cotton, F. Albert; Wilkinson, Geoffrey (1988). "23. Metal-to-metal bonds and metal atom clusters". Advanced Inorganic Chemistry (5th ed.). John Wiley and Sons. p. 1089. ISBN 0-471-84997-9.