[pure-silver] Re: Borax
- From: Gerald Koch <gerald.koch@xxxxxxx>
- To: "pure-silver@xxxxxxxxxxxxx" <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 11 Jul 2013 10:44:22 -0700 (PDT)
Hi Bob,
The name borax used by itself was never a trade name. The name is derived from
the Arabic boraq and appears in the writings of alchemists of the early middle
ages.
You will find the word borax (common name for sodium tetraborate) associated
with terms such as anhydrous and other hydration states all over the chemical
literature. It's use is not restricted to only the decahydrate. However as I
mentioned if no hydration state is mentioned the convention is to assume the
most stable form of any chemical.
BTW, there is also a pentahydrate.
Jerry
________________________________
From: BOB KISS <bobkiss@xxxxxxxxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Thursday, July 11, 2013 11:58 AM
Subject: [pure-silver] Re: Borax
DEAR
COR & JERRY,
Richard
and I already posted the following. Perhaps you have missed the posts or
chosen to ignore them but they make it clear:
“The only time there can be a question as to the
hydration of the compound in a formula is if it specifies Sodium Tetraborate
which can exist as either the anhydrous or the decahydrate. If it
specifies Borax it is, by definition, the decahydrate flavor.”
Sodium Tetraborate
is the chemical. Borax is a popular brand name which has become generic (like
Kleenex) for the decahydrate version of Sodium Tetraborate. So if anyone says
Borax
they are referring (whether they know it or not) to the decahydrate version,
not the anhydrous version. We all are all human and can make mistakes or
mistaken assumptions, even those people who write formulae.
So Borax specifically
means Sodium Tetraborate-decahydrate. If it says Sodium Tetraborate it can
mean either the anhydrous or the decahydrate.
As has also been
pointed out quite specifically by Daniel Bouzard, as it is used as a buffer in
FX37
the difference between the two will make less than .1 or .2 units difference in
pH, insignificant in photographic work. Further, someone else pointed out that
the anhydrous flavor of Sodium Tetraborate is soooooooooooo hydroscopic that it
does not remain anhydrous for very long so trying to use it is self defeating.
CHEERS!
BOB
________________________________
From:pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx]
On Behalf Of C.Breukel@xxxxxxx
Sent: Thursday, July 11, 2013 2:57
AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Borax
Hi Jerry,
I found that
annoying too: this anhydrous for the carbonate and no further specification on
the Borax, and I am not even a real chemist (a biochemist/molecular biochemist
actually, hard-core chemistry is 30 years ago for me, after that only DNA, RNA
and protein for me…;-..)..
Best,
Cor
From:pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx]
On Behalf Of Gerald Koch
Sent: donderdag 11 juli 2013 6:21
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Borax
I
find it curious that the formula specifies anhydrous sodium carbonate but makes
no mention of the form of the borax. The convention is to specify the
form when it is not the usual one as is done for the sodium
carbonate. That is that the monohydrate is the most commonly
used form. This would lead me as a chemist to assume that borax
decahydrate is to be used. Had it been intended that anhydrous/desiccated
borax be used then it would have stated this. But then Crawley 's
chemistry was a bit flakey from time to time.
Jerry
From:"C.Breukel@xxxxxxx"
<C.Breukel@xxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Wednesday, July 10, 2013
3:10 AM
Subject: [pure-silver] Re: Borax
Thanks
for the feedback guys, Jean-David: I too found that Wiki link, so I too assumed
it to be decahydrate.
The
reason for asking is that I am weighting out some chemistry for a friend to mix
FX-37. He was inspired by another friend who uses it all the time. Much to my
surprise when I could finally get in touch with the “source” (he was on
holiday) he replied that the Borax he uses : de borax is CAS: 1330-43-4.
M=201,22g/mol
So
that’s the anhydrous form, and there is almost a factor 2 weight difference
(381.38/201.22 * 2.5 gram
= 4.7 gram Borax per litre) so if you guys are right and it should be de
decahydrate form, my friend is using almost twice as much Borax as intended in
the original formula.
How
harmful is that, i.e. will it make the FX-37 faster or more contrasty
developer ?
FYI
FX-37:
Sodium
sulfite,
60.0 g
Hydroquinone,
5.0 g
Sodium
carbonate, anhydrous, 5.0 g
Phenidone,
0.5 g
Borax,
2.5 g
Potassium
bromide,
0.5 g
Benzotriazole,
1% solution, 5.0 ml
Best,
Cor
From:pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx]
On Behalf Of Gerald Koch
Sent: dinsdag 9 juli 2013 23:23
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Borax
The
tetrahydrate is the only form that is stable. Other forms will absorb
water to become the decahydrate. Twenty Mule Team borax is very pure and
can be used for photo purposes. Some years ago I wrote to US Borax and
they sent me a brochure of their products which included an analysis of
each. The main impurity of their borax is a very small amount of sodium
chloride.
Jerry
From:"C.Breukel@xxxxxxx"
<C.Breukel@xxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Tuesday, July 9, 2013 3:07
AM
Subject: [pure-silver] Borax
If
a formula like FX-37 calls for just Borax: is it the anhydrous form they refer
to or the hydrous one (8 or 10 H2O depending how you write the formula it
seems) ?
Thanks,
Best,
Cor
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