Three centuries after its discovery by alchemists, the crystal structure of mercury fulminate - an explosive detonation compound - has finally been determined. Out of date textbook and literature representations will have to be revised, according to Wolfgang Beck, Thomas Klapötke and their colleagues at the Ludwig Maximilians University in Munich, Germany. The team used X-ray crystallography to obtain a precise structure of mercury fulminate, known in German as Knallquecksilber, meaning literally "bang quicksilver". The crystal is orthorhombic and composed of separate Hg(CNO)2 molecules that are near linear: O−N≡C−Hg−C≡N−O. "We can unambiguously show that the molecules in the crystal have a stretched-out, nearly linear form," explains Beck, "They are not bent, and each mercury atom is not bound to two oxygen atoms, as they are amazingly still occasionally depicted in the literature."