[alt-photo] Re: Instability of dichromate, et al...was Re:"Moistened"

[Dirk-Jan Treffers]

Well, as one of the chemists on this list, I can only confirm what Marek is
telling.
For everyone who suddenly feels the urge to put a lighter at a dish with
some AmDichrom: the usual 'kids, don't try this at home' warning applies!
The chemical reaction itself is just fun to look at. And chemically
speaking, in perfect conditions, no hazardous chemicals are formed (for
those interested: *(NH4)2Cr2O7(s) → N2(g) + Cr2O3(s) + 4H2O(g), *meaning
that nitrogengas and water are formed in gaseous form, which you breath in.
But since nitrogen and water are also present in the air you breath, I don't
think this will have a major effect on your health ;-) ). The solid that is
formed, however, contains Cr(VI) ions.Those are very dangerous (the same
ions that are present in AmDichrom.) You already know the hazardous effects
of that stuff, I ussume: can cause cancer, dangerous for women who are
pregnant/unborn child/reproductive risk...etc). Now for the application of
gumprinting, these risks are neglectable when taking the right precautions.
But with the vulcano experiment, cleaning up the mess is quite more
difficult... The vulcano-effect also means that some of this solid that is
formed, is blown into the air which you breath...

But, thank God for the internet:
http://www.youtube.com/watch?gl=NL&hl=nl&v=q2VLIbU6rh4

so far my two cents to this topic!

kind regards,

Dirk-Jan

2010/1/9 Marek Matusz <marekmatusz at hotmail.com>

>
> Ammonium dichromate is an old "volcano demo" reagent. You can start the
> self-decomposition reaction by sticking a red hot nail to it, or perhaps a
> flame from the lighter and then if spews a green ash of chromium oxide in
> the air as ammonium dichromate is self-decomposing. DOne that a lot of times
> in the past, before all the regulations. Never had any issues with it.
> Heating it to very high temperatures in a closed container is however not
> advisable.
>
> I am sure a lot of more seasoned chemists on the list have seen the volcano
> demonstartion or done it.
>
> Marek
>
> > From: zphoto at montana.net
> > Date: Sat, 9 Jan 2010 08:25:32 -0700
> > To: alt-photo-process-list at lists.altphotolist.org
> > Subject: [alt-photo] Re: Instability of dichromate, et al...was
> Re:"Moistened"
> >
> > I myself have packed my am di in a box in a car trunk and made my husband
> travel with it through the deep South in 100 degree weather in a car in
> front of me (feeling guilty all the way) and he lived to tell the tale :)
> But YRMV (your results may vary).
> > Chris
> >
> > Christina Z. Anderson
> > christinaZanderson.com
> >
> > On Jan 8, 2010, at 9:40 PM, Judy Seigel wrote:
> > > I myself have lived, slept, shouted, and PERSONALLY EXPLODED, not to
> mention jumped up & down, cursed & rent my garments on numerous occasions in
> a room with lots of ammonium dichromate, especially the dry powder (here
> being called "crystaline"??), but other forms as well, and never got so much
> as a hiccup out of it.
> > > Judy
> >
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