in your element The germination of germanium Shawn C. Burdette and Brett F. Thornton explore how germanium developed from a missing element in Mendeleev’s periodic table to an enabler for the information age, while retaining a nomenclature oddity.

hen German chemist consistent with the German name of the Clemens Winkler analysed the other group 14 metalloid, silicium. Wmineral argyrodite that had been With the invention of the point-contact excavated from a mine near his hometown of transistor in 1947, germanium played a key Freiberg, he could not account for 7% of the role in solidifying the definition of metalloids total mass1. The balance of the contents was as well as ushering in the information age4. identified as silver (75%), sulfur (18%) and The same characteristics that contributed some minor impurities. In 1886, after many to the challenge in isolating element 32 and failed attempts to isolate the elusive substance, placing it on the periodic table are also the Winkler finally precipitated a sulfide complex attributes that impart it with semiconducting using a large excess of hydrochloric acid, and properties. For a time, the moderately rigorously interrogated the material2. uncommon element (~1.5 ppm in the Earth’s These investigations coincided with SWEDEN STOCKHOLM, KARLSSON, EMMA SOFIA crust) became a vital commodity, because it an era of confusion and clarification was easier to obtain in the necessary purity about the then-relatively-new periodic the same groups as lighter main-block and for the electronics industry than silicon table. Mendeleev’s seminal proposal for transition elements. Only four elements were until the 1960s. Although improvements element organization had appeared in known between barium and tantalum, and in silicon refining temporarily reduced the 1869, and an important part was the the arrangement at the time made Winkler’s industrial demand for germanium, recent empty spaces he had left for elements yet suggestion of eka-antimony and Mendeleev’s years have seen a resurgence in its uses. to be discovered. Two of those predicted of eka-cadmium seem eminently reasonable. Germanium now finds uses in optical fibres, elements, gallium and scandium, were Obtaining the atomic weight of germanium, polymerization catalysts, and Si-Ge alloys in discovered in 1875 and 1879 respectively, as Winkler noted in his first report1, would microchip manufacturing, with feature sizes and corroborative evidence was mounting. resolve the positioning problem. Ultimately it on the chips reaching 7 nm (< 60 Ge atoms). Nonetheless, some scientists still had was Meyer, with his assertion that germanium Over 100 years after its discovery, the doubts about Mendeleev’s periodic table. was in fact eka-silicium, who was proven placement of germanium with the other Recognizing that the missing component right by analyses of the physical properties metalloids along the dividing line between in argyrodite was a new element, Winkler of germanium, which perfectly matched the metals and non-metals seems prosaic, dubbed it ‘germanium’ and proposed nearly all of Mendeleev’s 1869 predictions even if its metallic nomenclature remains placing it between antimony and bismuth, for eka-silicium — including an atomic an aberration. ❐ based on chemical similarities with weight of 72. these known elements1. One look at In his extensive follow-up report on SHAWN C. BURDETTE is in the Department the modern periodic table makes this the identification and characterization of of Chemistry and Biochemistry, Worcester placement appear incongruous — but germanium2, Winkler reported having Polytechnic Institute, Worcester, Mendeleev’s table did indeed have such received objections to his proposed name Massachusetts 01609-2280, USA. an opening for ‘eka-antimony’ between because it had too much of ‘un goût de e-mail: [email protected] antimony and bismuth. After Mendeleev terroir’ — that is, it was too nationalistic. Twitter: @WPIBurdette learned of Winkler’s discovery, the two He resisted any change, citing that both scientists, together with German chemist gallium and scandium paid homage to their BRETT F. THORNTON is in the Department Julius Lothar Meyer, corresponded at length discoverers’ homelands. Although it was of Geological Sciences and Bolin Centre for about the new element’s anticipated and its root that was begrudgingly accepted, Climate Research, Stockholm University, actual properties. Mendeleev doubted some another aspect of the name could have 106 91 Stockholm, Sweden. of the initial hypotheses, even suggesting that invited scrutiny. Germanium, along with email: [email protected] the element might be eka-cadmium. selenium, tellurium and helium, is one of Twitter: @geochembrett These seemingly bizarre suggestions arose the few non-metallic element to carry the because Mendeleev’s tables wrapped the ‘-ium’ suffix in English3. This can seem References blanks for the then-unknown lanthanides into an odd choice as the title of Winkler’s 1. Winkler, C. Ber. Dtsch. Chem. Ges. 19, 210–211 (1886). original report, entitled ‘Germanium, Ge, 2. Winkler, C. J. Prak. Chem. 34, 177–229 (1886). 3. Thornton, B. F. & Burdette, S. C. Nat. Chem. 5, 350–352 (2013). a new non-metallic element’, plainly states 4. Enghag, P. in Encyclopedia of the Elements: Technical Data — he did not believe it was a metal1; yet it is History — Processing — Applications 923–933 (Wiley-VCH, 2004). Cu Zn Ga Ge As Se Br Kr Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In 244 NATURE CHEMISTRY | VOL 10 | FEBRUARY 2018 | www.nature.com/naturechemistry ©2018 Mac millan Publishers Li mited, part of Spri nger Nature. All ri ghts reserved.