Sodium sulfite desiccated" or "Sodium sulfite anhydrous

Discussion in 'B&W: Film, Paper, Chemistry' started by OMU, Jul 10, 2012.

  1. OMU

    OMU Member

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    Hello,
    I would like to play with some a amidoll paper developer.

    There are different recepies;
    unblinkingeye.com/Articles/Amidol/amidol.html

    Some with "Sodium sulfite desiccated" and some with "Sodium sulfite anhydrous.

    I hope anyone can tell me the differense about those cemicals. I have the anhydrous, can I use it instead of the desiccated?

    Thanks :smile:
     
  2. Ian Grant

    Ian Grant Subscriber

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    They are the same - both mean no water, the other form which really only appears in US publications is Crystalline (cryst) which is the heptahydrate form.

    Ian
     
  3. OMU

    OMU Member

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    Thanks Ian,
    Can I use the same weight for both of them, (sorry for my English )
     
  4. jochen

    jochen Member

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    Hello,
    Sodiumsulfite cryst. has 7 moles of crystal water and the molecular weight of 252, the anhydrous form has a molecular weight of 126. So you can take either 1 gr. Sodiumsulfite sicc. or 2 gr. of the crystalline form. The anhydrous form is much more stable at air, so the crystalline salt is virtually not available on the market. Sicc. is Latin and means "siccum" = dry.
     
  5. PhotoJim

    PhotoJim Member

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    "Dessicated", when it comes to chemicals, is an obsolete term that has now been replaced by "anhydrous". Both mean the same thing - without water molecules.
     
  6. Ian Grant

    Ian Grant Subscriber

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    Yes, they are the same chemical just a different term meaning the same thing.

    Ian