Vhin - 21-5-2012 at 21:57
Basically, just name any tips you know for keeping chemicals that are especially reactive (and difficult to store). It doesn't have to be any specific
chemicals, though if you have a specific chemical you want to know about, feel free to suggest it.
The one that I was wondering about was Ferrous Chloride (FeCl2). I know it can be kept in air-tight containers, but a lot of people have issues
getting a container truly airtight. So, one thing I thought about was adding in a small mass of elemental Iron when storing Ferrous Chloride, to
convert any Ferric Chloride that happens to be made back to Ferrous Chloride. Obviously, filter it before you use it, but would it work? Or would the
amount of Iron required make it impractical?
woelen - 22-5-2012 at 02:44
Ferrous chloride does not turn to ferric chloride in air, but to some oxychloride. The oxidizing species is oxygen from the air and not chlorine. Once
you have oxygen in your iron chloride, you cannot get rid of it anymore without a lot of work. The material then has deteriorated somewhat.
Ferrous chloride is a really nasty one to store. Each time when you open the container you know that it deteriorates somewhat further, due to oxygen,
getting into the container. Some chemicals should not be opened in air, but in a glove box with inert atmosphere.
I myself use multiple containers for sensitive chemicals. I keep the larger stock quantity in a big(ger) bottle and keep a working quantity in a small
bottle. The larger stock quantity only is opened for filling the smaller working bottle. The large stock quantity is kept in a high quality container
(glass) with a very tight cap, all of this in turn wrapped in a thick plastic sealed bag. So, only the small working quantity deteriorates each time
it is opened and in the case of bad contamination, only the working quantity suffers from it.
I use this strategy for my sulphuric acid (which attracts water and slowly dilutes), certain sensitive metal salts, such as FeSO4.7H2O, anhydrous
chlorides like ZnCl2, AlCl3 and CuBr2. Some chemicals I do not want at all. Among these are FeCl2.4H2O and chromium(II) salts. These chemicals are so
sensitive that each single opening of the container deteriorates the chemical so much that soon the chemical is useless.