Phosphinic Acid → Tricalcium Phosphate

Participants

Reaction Steps

An aqueous solution of 8.06 g 50 wt % H3PO2 reagent was combined with 6.00 g distilled water to form a clear, colorless solution in a 250 ml Pyrex beaker on a hotplate/stirrer. To this solution was added 19.23 g Ca(NO3)2.4H2O. The molar ratio of Ca/phosphate in this sample was 4/3 and the equivalent solids [as octacalcium phosphate, Ca8H2(PO4)66-5H2O] was 30.0 wt %. Endothermic dissolution of the calcium nitrate tetrahydrate proceeded under ambient conditions, eventually forming a homogeneous solution once the sample warmed to room temperature. Warming of the solution above 25° C. initiated a vigorous exothermic reaction as described in Example 1. After approximately three minutes, the reaction was essentially complete leaving a moist, white, pasty solid.

Provenance & Evidence