Zinc → Zinc Phosphate

An aqueous solution of 8.51 g 50 wt % H3PO2 in 8.00 g distilled water was prepared as described in Example 1. To this solution was added 28.78 g zinc nitrate hexahydrate salt, Zn(NO3)2.6H2O (ACS reagent, Aldrich Chemical Co., Inc. #22,873-7, CAS #10196-18-6), equivalent to 21.97 wt % Zn. The molar ratio of Zn/phosphate in this mixture was 3/2 and the equivalent solids level [as Zn3(PO4)2] was 27.5 wt %. Endothermic dissolution of the zinc nitrate hexahydrate proceeded giving a homogeneous solution once the sample warmed to room temperature. Further warming of this solution to >25° C. on a hotplate initiated a reaction in which the solution vigorously evolved red-brown acrid fumes of NOx(g). The reaction continued for approximately 10 minutes while the sample remained a clear, colorless solution, abated somewhat for a period of five minutes, then vigorously resumed finally resulting in the formation of a mass of moist white solid, some of which was very adherent to the walls of the Pyrex beaker used as a reaction vessel. The hot solid was allowed to cool to room temperature and was stored in a polyethylene vial.