If names of Gods would ever be assigned to the elements, then Janus - the two-headed god from Roman mythology - would be the ideal partner for bismuth. Opinions differ even when it comes to the name of the metal: In the German-speaking world, some call it „Wismuth" - meaning „the white mass", others talk of bismuth. As early as 1390 the name „Wesemut" already appeared in the German-speaking countries, by around 1530 the Latin speaking scholars called it „bisemutum". However, bismuth was considered only as a sub-variety of lead, tin or antimony for a long time until 1830, when the chemists Claude François Geoffroy, Johann Heinrich Pott, Carl Wilhelm Scheele and Torbern Olof Bergman detected it as a unique element. But even today bismuth production depends on lead or tungsten, from whose ores it is predominantly extracted. Despite its complex history, the current applications of bismuth are clearly outlined: The element is used mostly for alloys in metallurgy and in the pharmaceutical industry, including the gastrointestinal drug „Pepto-Bismol", where it has a weight proportion of 57 percent. It is surprising to see that lead and polonium are its immediate neighbours in the periodic table: One of them being highly toxic, the other deadly radioactive. This is also one of the great strengths of bismuth - it has similar properties to lead and other heavy metals, but unlike them is completely non-toxic according to current knowledge and is increasingly used as a lead substitute. A lead-bismuth alloy was used even in the fastest-ever mass-produced submarines - the boats of the Soviet Alfa-class with a speed of almost 45 knots: As a coolant for the submarine's onboard nuclear reactor. Approximately 7,500 tonnes of bismuth were produced in 2009, more than 60 percent in China, with the largest reserves estimated at 240,000 tonnes. It is an element with two common names, harmless on its own, but with highly dangerous neighbours: Janus would love it! For more information, visit: www.swissmetal.net

• published: 18 Jul 2013
• views: 0