Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Potassium octachlorodimolybdate is the inorganic compound with the formula K4Mo2Cl8. This red-coloured salt consists of potassium cations and the octachlorodimolybdate anion, Mo2Cl84 . The anion is of historic interest because it was one of the earliest illustrations of a quadruple bonding. The salt is usually obtained as the dihydrate. The reaction of the acetate with HCl was first described as providing trimolybdenum compounds, but subsequent crystallographic analysis confirmed that the product contains the Mo2Cl84 ion with D4h symmetry. The Mo---Mo distance is 2.14 Å.