MOLTEN LITHIUM-NITRATE POTASSIUM-NITRATE EUTECTIC - THE REACTIONS OF ALUMINUM, GALLIUM AND THALLIUM

Aluminium(III) chloride and sulphate reacted with the alkali nitrate eutectic forming alumina, with intermediate formation of two immiscible, oxide-containing layers in the case of aluminium(III) sulphate. Both chloride and sulphate anions stabilised aluminium cations by coordination. Aluminium nitride (A1N) was unreactive in pure melt, but reacted in both basic (NaOH) and acidic (K2S2O7) melts. Gallium(III) chloride and nitrate reacted with pure nitrate melts at temperatures which increased as chloride was added. However, additions of bromide and nitrite caused reaction at lower temperatures. In each case the product was gallium(III) oxide, but in various crystal modifications. Thallium(I) nitrate did not react in the pure melt below 500-degrees-C, following the expected trend with increase in cation size and decrease in oxidation state. Both thallium and gallium cations were stabilised by coordination with nitrate when dissolved in the melt.