The “Green of Scheele”made in the late 18th century by the Swedish chemist Skeletonwas a compound very shiny which immediately collected a great success given its shade similar to emerald green And its possible use in painting, in upholstery on wallpapers, but also on clothes, toys, in some furnishing components and even in dessert decorations. The “Green of Scheele”however, proved to be highly toxic: contained arsenic. During the 19th century, its use took hold in Europe and even overseas, it was also used on the covers of some books, now mapped in the Poison Book Project. Only towards the end of the century, after numerous cases of poisoning due to the prolonged exposure to the toxic gases issued by Arsenic -based pigmentdiscovered its poisonous nature, and only in 1933 Its lethal potential was decreed.
Among the possible cases of “illustrious” characters poisoned by the green pigment, there is also Napoleon: one of the hypotheses regarding his death, in fact, is that he was poisoned due to the long exposure to his wallpaper which was obviously green.
The green of Scheele and other poisonous green
Sweden, 1775: the chemist Carl Wilhelm Scheele Prepare for the first time a mixture of yellow-green color, a mixture of copper arsenites indicated with the formula Cuhasus3 and, other times, with Cu3(ASO3)2 o Cu (ASO2)2. The color is vivid, brilliant and very similar to emerald green: for this reason, it immediately has great success. A beautiful green, which will go down in history just like “Green of Scheele”but highly dangerous: the amount of arsenic contained in the pigment, in fact, makes this color very poisonous and unstable in the presence of other substances.
But to get to understand that this shiny green is very toxic, it will still take several years, so much so that in 1814 The German company Wilhelm Dye and White Lead Companybased in Schweinfurt, even puts the pigment on the market. The “Green of Schweinfurt” – Copper acetate with chemical formula Cu (C2H3OR2)2· 3Cu (ASO2)2 – It will be used to dye fabrics, walls, toys, soap, decorations for desserts, but also for book covers.
Beautiful and cheap, the poisonous green in the following 50 years really made the tour of the world: despite being known the toxicity of the Arsenico – just think that a Paris It was used for deduct the sewershence the name of “Green Paris” – But it is not reflected that prolonged exposure can be fatal for humans.
The toxic effects of exposure to poisoned green
The first to expose itself against the massive use of this pigment was the German chemist Leopold Gmelinwhich in 1839 he published an article in which he declared the use of the wallpaper green because the fermentation of the organic material present in the paper Free Esasilations of Arsenico. In those same years, many workers and upholsters showed signs of poisoningbut unfortunately Gmelin was not taken into consideration.
The poisoned green could even have played a role in the Death of Napoleon Bonaparte: as reported by this article in which we investigate the possible causes of death, traces of arsenic have been found in Napoleon’s hair. One of the hypotheses formulated is precisely what the Parati paper of his room in Longwood Houseon the island of Sant’Elena where he was exiled, they had released toxic gases of arsenic, intoxicating him until his death.
The discovery of green toxicity to the Arsenic in 1933
Bartolomeo GosioItalian microbiologist and biochemical, at the end of the 19th century he hypothesized that the mold on the walls They released toxic gases from the pigment – not surprisingly Napoleon’s room was a wet and unhealthy place – but only in 1933 The English chemist Frederick Challenger identified the toxic compound as trimetilarsina – or Trimetilarsano – composed of Organarsenic (III)formula AS (CH3)3abbreviated in ASME3.
