Virus - 26-4-2006 at 13:29
I am almost sure that it is possible to concentrate ortho-phosphoric acid by heating it, at least to 85%. But can I evaporate all the water and get
100% pure crystals of H3PO4? Somebody has told me it decomposes at higher temperatures.
12AX7 - 26-4-2006 at 14:41
Yep, to pyrophosphoric acid and so on. From what I've heard, phosphoric never crystallizes, it just make syrupy liquids or, with less hydration,
glasses. Besides P2O5 of course, which is relatively volatile and crystalline. As with all things, cooled slow enough it should be able to
crystallize.
Tim
turd - 27-4-2006 at 10:30
Of course you can crystallise dry phosphoric acid. A procedure for dry phosphoric acid is given in Inorganic Syntheses.
Organikum - 27-4-2006 at 15:50
150°C for the anhydrous state AFAIK.