Uranyl Platinocyanide, UO₂.Pt(CN)₄

Uranyl Platinocyanide, UO₂.Pt(CN)₄.4(or 5)H₂O, has been prepared by double decomposition of solutions of uranyl sulphate and barium platinocyanide. The green, filtered solution, upon evaporation at room temperature in a desiccator, deposits red crystals possessing a strong green metallic reflection.

If, however, the solution is concentrated on the water-bath, a yellow crystalline substance is obtained, which passes into the red-green form on cooling. Probably these changes are consequent upon variation in hydration.

The temperature of transformation of the red-green hydrate to the yellow salt is 39° C.