the birth of cyanide
"Centuries later cyanide became more readily available in large and lethal quantities. That happened, in part, due to some experiments by a German painter who in 1704 was only trying to improve the colors on his palette.
"The artist, one Heinrich Diesbach, was a born experimenter. He spent hours in the laboratory of a Berlin chemist, trying to create a new shade of red paint. He swirled together wilder and wilder mixtures, eventually mixing dried blood, potash (potassium carbonate), and green vitriol (iron sulfate), then stewing them over an open flame. He expected the flask to yield a bloody crimson, but instead a different brilliance appeared—the deep violet-blue glow of a fading twilight. Diesbach called the vivid pigment Berlin blue; English chemists would later rename it Prussian blue.
"Almost eighty years later a Swedish chemist mixed Prussian blue with an acid solution, heated the witchy, foaming result, and produced a colorless gas, undetectable but for a faint smell of bitter almonds. The gas easily condensed into a clear liquid that, even diluted with water, was an exceptionally potent acid. That corrosive liquid became popularly known as Prussic acid, although scientists preferred to call it hydrocyanic acid (from the Greek words hydro for water and kyanos for blue).
"The gas was hydrogen cyanide (HCN), a deceptively simple, spectacularly lethal bundle of hydrogen, carbon, and nitrogen atoms."