Dichromate salts, toxicity

Another type of nitrocellulose powder used for some time which eventually disappeared from the market was a semi-colloidal nitrocellulose powder containing inorganic salts such as potassium or barium nitrate (e.g. Poudre T in France, with 2% potassium nitrate) or with dichromates (e.g. Poudre J in France with 14% ammonium dichromate and 3% potassium dichromate). The dichromate powder was very sensitive to friction and its dust contained toxic dichromates. 

A specific type of electrostatic anion receptor constitutes the compounds capable of chromate (CrO -) or dichromate (Cr2Oj ) recognition. These anions are particularly important because of their toxicity and the presence of these pollutants in the environment (waste water and soils). The corresponding receptors are based on the protonated amines [68,69] (such as 54), protonated forms of similar compounds [70,71] or on the quaternary ammonium salts [72] of type 55. Thus, ammonium salt 54 (in the form of chloride) can transfer chro-... 

See under COPPER AND ITS SALTS Lead Dichromate, PbCr207, mw 423.23 brick red or brn-red,amorph or cryst pdr mp( ) decomp by w sol in ale or alkalies(Ref 5) can be prepd by treating Pb chromate with a coned soln of chromic acid or by other methods (Ref 1). It is a powerful oxidizer and reacts vigorously when heated with reducing materials when heated to decompn, it emits highly toxic fumes of lead(Ref 4) can probably be used for the same purposes as PbCr04, namely in pyrotechnics... 

Sodium dichromate dihydrate Highly toxic, cancer suspect agent Chromic acid, disodium salt, dihydrate (8,9) (7789-12-0)... 

Chromium in wastewaters is usually present in its most oxidized form, hexavalent chromium(VI). This is the form that is most toxic to humans. It is usually present as the chromate ion, HCrO, at pH between 1.5 and 4, and CrO above pH 4.0, or it may be present as dichromate, Cr O.. The dichromate is also in equilibrium with singly dissociated chromate. These salts are highly soluble. 

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