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Photo Forum / Film Photography / Darkroom / April 2005Does Boric Acid equals Boric Acid, Crystal
In the formula of F-5 fixer, there is a Boric Acid, Crystal. But I only got Boric Acid (without the 'crystal' on the label). My question is, is the Boric Acid(H3BO3) actually Boric Acid, Crystal? If not, how do I convert the molecular weight between them? For example, the F-5 formula say that I need 7.5g Boric Acid crystal, so how many Boric Acid I actually need? Thanks in advance. - narke > In the formula of F-5 fixer, there is a Boric Acid, Crystal. But I > only got Boric Acid (without the 'crystal' on the label). My question > is, is the Boric Acid(H3BO3) actually Boric Acid, Crystal? If not, how > do I convert the molecular weight between them? For example, the F-5 > formula say that I need 7.5g Boric Acid crystal, so how many Boric Acid > I actually need? There is little point in figuring out how to convert molecular weights, because if it is not the crystalline form, it is too difficult to get the powder to dissolve.  Signature.~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 23:20:00 up 2 days, 13:36, 3 users, load average: 4.22, 4.30, 4.27 >>In the formula of F-5 fixer, there is a Boric Acid, Crystal. But I >>only got Boric Acid (without the 'crystal' on the label). My question [quoted text clipped - 6 lines] > because if it is not the crystalline form, it is too difficult to get > the powder to dissolve. THe 'crystal' doesnt mean anything, chemically. Is your boric acid not crystalline? If it's liquid, then it will be a diluted boric acid solution. Scott. > THe 'crystal' doesnt mean anything, chemically. Is your boric acid not crystalline? If it's liquid, then it will be a diluted boric acid solution. I can not tell if or not the boric acid is crystalline or powder for I have not open the cover now (I plan to open it just when I need to use). I can only tell you that's not liquid and the lable is H3BO3. With these information can you deduce that is or not crystalline? Thanks >>THe 'crystal' doesnt mean anything, chemically. Is your boric acid >> not crystalline? If it's liquid, then it will be a diluted boric acid [quoted text clipped - 3 lines] > have not open the cover now (I plan to open it just when I need to > use). I can only tell you that's not liquid If it's not liquid, then it's crystalline. Perhaps I should have said liquid or solid. If it's solid, then it's crystaline, i.e. dry, and you can ad it as per the number of grams in the recipe you have. > and the lable is H3BO3. With these information can you deduce that > is or not crystalline? Is it in a soft sachet, or a hard plastic container? If it's soft, then squeeze it... if it feels dry, then it's crystalline. If it feels wet, as in liquid form, then it's not crystalline. When they say crystalline, they mean in crystal form, or 'dry'. Scott. > If it's not liquid, then it's crystalline. Perhaps I should have said liquid or solid. If it's solid, then it's crystaline, i.e. dry, and you can ad it as per the number of grams in the recipe you have. > Is it in a soft sachet, or a hard plastic container? If it's soft, then squeeze it... if it feels dry, then it's crystalline. If it feels wet, as in liquid form, then it's not crystalline. When they say crystalline, they mean in crystal form, or 'dry'. Thank you. You precisely answered my question. It's in a hard plastic container and surely dry. By your information, I deduce its crystalline. Boric Acid comes in a granulated form which has a different hydration than the crystaline form. Granulated Boric is nearly impossible to dissolve in water. The crystals are actually not dry, there is the water of hydration in it. Dessicated or powdered Boric is usually metaboric acid. I suppose Boric could be put up in a liquid concentrate but I sure can't find any in the chemical catalogues. Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com God! I was confusing! I think same substance get same molecular formula, so could you fill the table below: 1) the molecular formula of Boric Acid, crystals: ______________ 2) the molecular formula of Boric Acid, granulate: _______________ 3) the molecular formula of Boric Acid precisely required in F-5 fixer: ________________ So I can determind the Boric Acid on hand is or not what I need for making F-5 mixer. Regards, narke > God! I was confusing! I think same substance get same molecular > formula, so could you fill the table below: > > 1) the molecular formula of Boric Acid, crystals: ______________ > 2) the molecular formula of Boric Acid, granulate: _______________ These are the same. Granular, crystaline, dry... all the same. It's not a different formula, it's just the phiscal form. It's either crystaline/dry/granular, or it's in solution (i.e. the crystaline/dry/granular form dissolved in water). > 3) the molecular formula of Boric Acid precisely required in F-5 > fixer: ________________ The forumla doesnt change regardless of where it is or what form it's in. It's always H3BO4. > So I can determind the Boric Acid on hand is or not what I need for > making F-5 mixer. If you have a recipe that requires an amount in grams, and your container is full of dry boric acid, then measure out your boric acid in grams. If your boric acid is in liquid form, then let me know the concentration and I'll tell you how to work it out (the concentration should should be written on the packet as either as a number, with a unit of 'g/L' (grams per litre), 'M' (molar), 'N' (normal). Scott. >> God! I was confusing! I think same substance get same molecular >> formula, so could you fill the table below: [quoted text clipped - 6 lines] > crystaline/dry/granular, or it's in solution (i.e. the > crystaline/dry/granular form dissolved in water). This is not correct. Just as with sodium carbonate which is available dessicated, monohydrated, and decahydrated, boric acid is available in several forms as well. I was unaware it was even available commercially in liquid form. In any case, it is available as dessicated powder that dissolves poorly in water, and in crystalline form (probably hydrated) that dissolves readily in water. >> 3) the molecular formula of Boric Acid precisely required in F-5 >> fixer: ________________ [quoted text clipped - 15 lines] > > Scott. Signature.~. Jean-David Beyer Registered Linux User 85642. /V\ PGP-Key: 9A2FC99A Registered Machine 241939. /( )\ Shrewsbury, New Jersey http://counter.li.org ^^-^^ 06:30:00 up 4 days, 20:47, 3 users, load average: 4.33, 4.15, 3.79 ... >Just as with sodium carbonate which is available >dessicated, monohydrated, and decahydrated, boric acid is available in >several forms as well. I was unaware it was even available commercially >in liquid form. In any case, it is available as dessicated powder that >dissolves poorly in water, and in crystalline form (probably hydrated) >that dissolves readily in water. ... mar3005 from Lloyd Erlick, Borax is a similar compound. I had an unfortunate experience with anhydrous borax. I got a good deal on a twenty five kilogram bag, and discovered it would not dissolve in water no matter what I did. This seems to be a property of borates. I certainly don't know enough about chemistry to understand or explain. regards, --le Signature________________________________ Lloyd Erlick Portraits, Toronto. voice: 416-686-0326 email: portrait@heylloyd.com net: www.heylloyd.com ________________________________ >>> God! I was confusing! I think same substance get same >>> molecular formula, so could you fill the table below: [quoted text clipped - 11 lines] > dessicated, monohydrated, and decahydrated, boric acid is available > in several forms as well. I dont think that is right, either. Just to clarify... we're talking about boric acid, H3BO4, aren't we? Not a sodium salt of boric acid, i.e. a tetraborate or something like that? Boric acid doesnt have a hydration state. Your example has a hydration state because it's a sodium salt. Boric acid salts (borates) often have hydration states. Boric acid can either be in solid form, or dissolved in water as solution of boric acid... but still boric acid. You can produce more or less finely divided crystals of dry boric acid, but it's still boric acid. It is true that the powdered (finely divided) form is harder to dissolve, but you should be able to dissolve it by warming the solution with stirring. It will dissolve to around 40g/L. > I was unaware it was even available commercially in liquid form. Not really liquid form, but a boric acid solution. > In any case, it is available as dessicated powder that dissolves > poorly in water, and in crystalline form (probably hydrated) that > dissolves readily in water. Yes, all this is getting off the topic. You can weigh out your solid boric acid to the amount you have written in your recipe, and it will work. Scott. > God! I was confusing! I think same substance get same > molecular [quoted text clipped - 14 lines] > Regards, > narke The stuff you have is right for F-5 or for making buffered D-76. Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com Thanks for all your help. I understood. H3BO3 is the crystaline type. The powdered variety should be avoided for photographic purposes since it dissolves with great difficulty. -- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com H3BO3 is the crystaline type. The powdered variety should be avoided for photographic purposes since it dissolves with great difficulty. -- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com Boric acid crystals dissolve much easier than the powder form. That's the only difference. > In the formula of F-5 fixer, there is a Boric Acid, Crystal. But I > only got Boric Acid (without the 'crystal' on the label). My question [quoted text clipped - 7 lines] > - > narke |
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