Potassium octachlorodimolybdate

Potassium octachlorodimolybdate
Potassium octachlorodimolybdate
Properties
Molecular formula Cl8K4Mo2
Molar mass 631.9 g/mol
Appearance red crystals
 YesY octachlorodimolybdate (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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 compound is prepared in two steps from molybdenum hexacarbonyl:[1][2]

2 Mo(CO)6 + 4 HO2CCH3 → Mo2(O2CCH3)4 + 2 H2 + 12 CO
Mo2(O2CCH3)4 + 4 HCl + 4 KCl → K4Mo2Cl8 + 4 HO2CCH3
The octachlorodimolybdate(II) anion, [Mo2Cl8]4−, which features a quadruple Mo-Mo bond

The reaction of the acetate with HCl was first described as providing trimolybdenum compounds,[3] but subsequent crystallographic analysis confirmed that the product contains the Mo2Cl84− ion with D4h symmetry. The Mo---Mo distance is 2.14 Å.[4]

References

  1. ^ A. B. Brignole, F. A. Cotton, Z. Dori (1972). Rhenium and Molybdenum Compounds Containing Quadruple Bonds. "Inorganic Syntheses". Inorg. Synth.. Inorganic Syntheses 13: 81–89. doi:10.1002/9780470132449.ch15. ISBN 9780470132449. 
  2. ^ Girolami, G. S.; Rauchfuss, T. B. and Angelici, R. J. (1999). Synthesis and Technique in Inorganic Chemistry. Mill Valley, CA: University Science Books. ISBN 0935702482. 
  3. ^ G.B. Allison, I.R. Anderson, and J.C. Sheldon (1967). "The Preparation of Halogenotrimolybdate(II) Compounds". Australian Journal of Chemistry 20 (5): 869–876. doi:10.1071/CH9670869. 
  4. ^ Jurij V. Brencic and F. Albert Cotton (1969). ""Octachlorodimolybdate(II) Ion. Species with a Quadruple Metal-Metal Bond". Inorg. Chem. 8: 7–10. doi:10.1021/ic50071a002.