Molybdenum VI by the Thiocyanate Method

Theory Molybdenum (VI) is mostly converted to molybdenum (V) when an acidic solution of the former is treated with tin (II) chloride preferably in the presence a little Fe2+ ion. The resulting molybdenum (V) form a red complex with thiocyanate ion as follows  

Consequently, the red-complex is extracted with either solvents possessing donor oxygen atoms, such as 3-methyl butanol. However, Mo (VI) may also be extracted with diethyl ether-an oxygenated solvent, because it yields the maximum percentage extractive with 7.0 M NH4 SCN as could be seen from the following Table 27.2. 

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