When KSCN is added to molten NaNO3 -KNO3 eutectic within the range of 230-316°C, a complex and a relatively violent chemical reaction takes place until a KSCN concentration of ca. 1 mequiv KSCN/100 g eutectic has been added; further addition produces only a small residual chemical reaction. The reaction yields NO2, SO24 ions and basic ionic species in the melt and NO2, CO2, (CN)2, N2O and minor quantities of other gaseous products. The reaction is interpreted in terms of ionic equilibria involving NO, NO2, SCN, O22, O2, O2 and O2- ions and O2 as principal reacting species.