Potassium octachlorodimolybdate
Potassium octachlorodimolybdate is an inorganic compound with the chemical formula . It is known as a red-coloured, microcrystalline solid. The anion is of historic interest as one of the earliest illustrations of a quadruple bonding. The salt is usually obtained as the pink-coloured dihydrate.
File:Octachlorodirhenate-3D-balls.png|thumb|left|150px|The octachlorodimolybdate anion, 4−, which features a quadruple Mo-Mo bond
The compound is prepared in two steps from molybdenum hexacarbonyl:
The reaction of the acetate with HCl was first described as providing trimolybdenum compounds, but subsequent crystallographic analysis confirmed that the product contains the ion with D4h symmetry. The Mo–Mo distance is 2.14 Å.
