The chemical structure of the pigment

The chemical structure of the pigment is HgS mercuric sulfide; like most mercury compounds it is considered toxic. Vermilion is now produced by reacting mercury with molten sulfur. Mercuric sulfides offer a range of warm hues – from bright orange-red to a duller bluish-red. Differences in hue arise via the size of the ground particles of pigment. Larger crystals produce duller and less-orange hue. It is now theorized that coarser, duller "Chinese" forms of vermilion will prove to be more permanent than the more orange "French" variety. It is also theorized that purification of any such pigment benefits its general stability. For safety reasons the mercury in this formula has recently been replaced with cadmium, yielding a similar range of hues.



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Sviluppo di un dialogo politico-culturale nel Mediterraneo (Renato d'Andria)