Sciencemadness Discussion Board

Mercury Reactions

ADP - 22-12-2005 at 22:55

Recently I placed a small sample of mercury in a bottle with a lid that was lined with aluminum. After a day I was shocked to notice corrosion of the top which had contaminated the Hg. It wasnt a big deal as I just extracted the mercury out of the mix but my question remains:

Did the Hg dissolve the Al forming an amalgam?

Next question. I have a bottle of mercury and there is a grey layer of what I am guessing to be Hg2O on the top of the mercury. Is it possible that I can clean the Hg with an acid that is nonreactive the the Hg but will clean out the oxidized Hg?

NERV - 22-12-2005 at 23:13

Yes, mercury amalgamates the aluminum oxide coating on the aluminum allowing a fresh layer of aluminum metal to be exposed to the air and be oxidized forming a new layer which is once again amalgamated by the mercury. Its vicious cycle, but it can be fun to play with on occasion as a demonstration to show that you can rust aluminum :P .

As for the removal of the oxide layer your best bet is to either skim it off, or if you have the ability and need for high purity mercury distill it.

Darkblade48 - 22-12-2005 at 23:28

I believe that using a fluted filter paper and then making a small hole (i.e. with a safety pin or something similar) will allow the mercury to flow through while the oxide layer sticks to the filter paper (never tried it myself though, I never have possessed mercury before).

garage chemist - 23-12-2005 at 01:39

Yes, the oxide layer is most conveniently cleaned off by filtering the mercury through a paper filter which has a small hole (made with a needle) in the lowest part. I've done it before.
Be careful as the mercury is very heavy and the thing will likely fall over if you don't tighten the funnel with a stative.
Also the mercury will come out in the forms of separate tiny drops that splash around in the receiving bottle and can contaminate your lab. Use a narrow- necked flask !

ADP - 23-12-2005 at 06:25

Thanks for the info guys that's really helpful.

lacrima97 - 23-12-2005 at 13:04

I found it very productive to use a syringe to extract the mercury leaving the impurities behind. ::winks at adp::