Working with ferric chloride hexahydrate

Factual Questions
1

I asked somebody to pick up some ferric chloride solution, but what they brought me is FeCl[sub]3[/sub] + 6H[sub]2[/sub]O.

I am not exactly sure what I can do with this, or if I can use it to etch a copper-clad circuit board. For one thing, I can’t even get it out of the bottle. It seems to have all solidified into a solid mass at the bottom, with a thin layer of yellowish liquid on the top. And all of that is inside a plastic bag within the bottle. It doesn’t look at all like the dry yellow crystals on the wiki page.

Here a pic of what I am dealing with.

I noticed on the wiki page that the melting point is a mere 37°C. Is it possible it was left in a hot place and melted and then re-solidified into an impenetrable chunk within the bottle? Could I set the bottle in a hot water bath and make the stuff workable again?

Thanks in advance to any chemical-science-type people who can provide me with some clues.

2

IANAChemist, but I would guess that this is one of those situations where the two substances exist in a dynamic equilibrium, and that it is impossible, or nearly so, to have a pure sample of one without the other, and that a container labeled as one is indistinguishable in its contents from one labeled as the other. Sort of like carbonic acid vs. aqueous carbon dioxide.

That said, I have no idea what the solid mass or yellowish liquid you have are, or whether they’ll work for what you want.

3

There are better and less-messy solutions for etching copper, which I would be happy to share.
Ferric Chloride makes a tremendous mess, and will wreck stainless steel, so I would avoid it.

4

I am a chemist.

Hydrated salts are the norm (on sigma-aldrich the anhydrous version is 10-100x as expensive)- you just scrape out the mass that you need. If the concentration and mass calculation assumed anhydrous, you just have to do the new calculation using a molecular mass of 270 g/mol (hexahydrate) vs. 162 g/mol (anhydrous).

You can use an old butter knife to scrape or break the solid into the more manageable sizes.

5

I wish I could. I tried using a bar spoon to dig into the substance and couldn’t break a single piece free. It’s like a block of cured cement in the bottom of the bottle. It seems the only way this stuff is coming out is if I break the bottle.