Sciencemadness Discussion Board

Amalgamation using Mercuric Iodide (HgI2)

Adam.sh - 11-2-2014 at 18:05

I know that aluminum amalgamation using mercury chloride or mercury nitrate works. But, I was wondering if Mercuric Iodide (HgI2) works for aluminum amalgamation and has anyone ever tried it before?

Brain&Force - 11-2-2014 at 18:12

It's not very soluble in water (<100 ppm), so it probably would take a very long time. It's also a waste of the iodide - the chloride is cheaper.

An easy way to make a mercury amalgam is to just add aluminum metal to mercury. But if you can, use gallium instead. It's far less toxic.

Adam.sh - 11-2-2014 at 19:54

swim would probably have to use an alternative for HgI2 then. Which mercury salt is the right one for the amalgamation Mercury(I) nitrate or Mercury(II) nitrate?

bfesser - 11-2-2014 at 19:55

We don't allow "SWIM" here. Please review the forum guidelines (link in sig.).

Paddywhacker - 11-2-2014 at 23:46

Mercuric iodide is, indeed only sparingly soluble in pure water, but it is quite soluble in aqueous potassium iodide to form a complex.

Panache - 13-2-2014 at 19:16

I have generated many al/hg amalgams in my time and I have always used mercuric iodide. Its a far prettier colour and its solubility in alcohol and alcohol solutions is easily high enough.
I use it because it is pricelessly simple to make. Place one part mercury metal and two parts iodine in a test tube. stopper. Come back in a few days, red mercuric iodide. If you want it straight away you can grind the two together and the elements combine readily.

Organikum - 13-2-2014 at 22:48

Adding metallic mercury to some 50% nitric acid and not inhaling the fumes, then using this to amalgamate Al in water or alcohol.
Works always, relieable and fast.
If this is now the (I) or (II) nitrate I confess I never spent a thought on.

But all mercury salts work, solubility is secondary. Mercury alone is not really the hit, but some nitric acid or some HCl and a pinch of nitrate help it to get on the way.

The amalgamation is cake from the mercury side of the fence, the problems blamed on the mercury are IMHO virtually always to blame on the aluminium in special the stupid foil which still is believed to be suitable.
Get some good 99,9% Al granules and amalgamation will be the least of your troubles, the whole reaction will then be troublefree most probably.

/ORG

Panache - 17-2-2014 at 03:32

Quote: Originally posted by Organikum  


The amalgamation is cake from the mercury side of the fence, the problems blamed on the mercury are IMHO virtually always to blame on the aluminium in special the stupid foil which still is believed to be suitable.
Get some good 99,9% Al granules and amalgamation will be the least of your troubles, the whole reaction will then be troublefree most probably.

/ORG


Couldn't agree more, also pH dropping into the acidic can quickly nullify an active amalgam.
Quality electrical aluminium wire, once stripped makes excellent aluminium reagent also. It is always tres pure and by choosing different thickness you can control your surface area and hence your reaction rate.
As an aside Org, I believe your technique using nitric would be effective in producing an amalgam, regardless of whether or not the fumes where inhaled!

zig - 17-2-2014 at 23:53

So would the lower solubility of HgI2 cause its resulting amalgam to occur more slowly / managably than for example, an amalgam using HgCl2? I imagine the quantity of mercury salt used stays consistent without having to adjust for its particular anion(s), is this correct?

Brain&Force - 18-2-2014 at 19:55

Wouldn't it be possible to produce mercuric chloride by addition of mercury to hydrochloric acid and hydrogen peroxide (both of which are more easily available in the US)? That would make it easier.

Panache - 19-2-2014 at 03:48

Quote: Originally posted by zig  
So would the lower solubility of HgI2 cause its resulting amalgam to occur more slowly / managably than for example, an amalgam using HgCl2? I imagine the quantity of mercury salt used stays consistent without having to adjust for its particular anion(s), is this correct?


You can add too little I imagine and I have seen papers where ridiculous amounts ( in grams of hg slt per 10g al or something silly)
Shulgin always used a few grains of NaOH before adding the hg slt.
The mot important factor governing reaction rate in these things(heterogenous rxn involving solid surface) is surface area and in the al/hg case this very easily adjustable.