Karkov
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phosphomolybdic acid synthesis
When synthesizing PMA why does it sometimes change to green and sometimes yellow? I have done several experiments but can not find a correlation on
why it’s doing that when each experiment is the same.
[Edited on Apr04-10-2019 by Karkov]
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CharlieA
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Molybdenum exhibits many oxidation states with, generally, characteristic colors. See for example https://en.wikipedia.org/wiki/Molybdenum#Chemical_properties... Is the preparative procedure that you are following published? If so, does it
suggest the colors of various possible products or by- products?
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j_sum1
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Green??
Blue phosphomolybdates are famous -- often referred to as molybdenum blue, although this title serves a wide range of different species. Their
structures are really interesting and have very high molecular mass and are extremely vivid in colour. Thus they serve as a means for titrating
phosphate compounds.
My guess is that you have some of these included in your mixture -- probably as a result of something reducing the yellow compound.
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![[*]](images/xpblue/default_icon.gif){kind=icon}
