Quadruple bond 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 double bonds and triple bonds. Stable quadruple bonds are most common among the transition metals in the middle of the d-block, such as rhenium, tungsten, molybdenum and chromium. Typically the ligands that support quadruple bonds are π-donors, not π-acceptors. Chromium(II) acetate, Cr("μ"-OCCH)(HO), was the first chemical compound containing a quadruple bond to be synthesized. It was described in 1844 by E. Peligot, although its distinctive bonding was not recognized for more than a
Quadruple reed to play". Presumably a quadruple reed is folded twice, in opposite directions, instead of once (\/\ or \/\/ instead of \/ shaped), or either folded twice in the same direction or wrapped around (◎ instead of ○ shaped). Both options could result in what may be considered a doubly thick double reed. Quadruple reed A quadruple reed is a type of reed by means of which the sound is originated in various wind instruments. The term "quadruple reed" comes from the fact that there are four pieces of dried palm leaf vibrating against each other, in pairs. A quadruple reed,