Redox for molybdenum

1. Nov 28, 2004

chem_tr

Hello,

Anyone know something about Molybdenum(V) ions?

1n our university, we instruct an experiment to students, in which ammonium molybdate ($\displaystyle (NH_4)_2MoO_4$) is reacted with tin chloride with hydrochloric acid. A redox reaction occurs, to my knowledge it should be like that:

$$2(NH_4)_2MoO_4 + SnCl_2 + 12HCl \longrightarrow 2MoOCl_3 + SnCl_4 + 6H_2O + 4NH_4Cl$$

This reaction produces a blue colloidal solution, in which we are sure that molybdenum(V) ions are present. Is this compound the best stable molybdenum(V)-bearing one?

Thank you.

2. Nov 29, 2004

Staff: Mentor

Have you considered $$\displaystyle [NH_4]_2[MoCl_5(H_2O)]$$

I could not find any information on heat of formation or stability, but I have seen this compound referenced.

I also found a comment concerning $$Mo_2O_5 \cdot xH_2O$$ which states blue colloidal solution.

Last edited: Nov 29, 2004
3. Nov 30, 2004

Gokul43201

Staff Emeritus
I think Mo(V) is among the least common of its oxid. states. 2, 3, 4 are more common, I think.

However, I'm pretty sure Mo forms fairly stable pentahalides (MoCl5 for sure...and a few others too, I believe) because some of them get used for catalysis.

So, in my opinion, MoCl5 is also a possibility in your reaction...but I have no idea what color that is.

Is the blue colloid stable under heating ?