Arseniate of iron, Fe3As2O8, partially oxidised.

Characters. - A tasteless amorphous powder of a green colour.

Solubility. - It is insoluble in water, but readily dissolved by hydrochloric acid.

Reactions. - The solution in hydrochloric acid gives a copious light-blue precipitate with the yellow prussiate of potash (ferric), and a still more abundant one of a deeper colour with the red prussiate of potash (ferrous). A small quantity boiled with an excess of caustic soda and filtered gives, when exactly neutralised by nitric acid, a brick-red precipitate on the addition of solution of nitrate of silver (arseniate).

Dose. - 1/16 to 1/2 grain.

Uses. - Used when we wish to employ arsenic and iron together, as in skin-diseases in anaemic subjects.