in your element Homely Brett F. Thornton and Shawn C. Burdette consider holmium’s hotly contested discovery and later obscurity.

n 1878 Marc Delafontaine, a Swiss native working in Chicago, noticed previously Iunknown emission lines when studying a extract of samarskite ore. This observation alone was not enough to claim that element 67 had been discovered — newly observed spectral lines often heralded the identification of a new element, but it was not unusual for the same element to be ‘discovered’ multiple times with different spectral lines. Such spurious element discoveries appeared frequently in the late nineteenth century. Nevertheless, Delafontaine’s observations were confirmed by Jacques-Louis Soret, NATUR, OXYRIA EMMA S. KARLSSON, who was working in Switzerland with five more). Former Stockholm pharmacist useful for surgery because water-laden extracted from gadolinite ore. Carl Wilhelm Scheele found oxygen before tissues absorb the energy within half Delafontaine suggested the name philippium Priestley, even though the latter published a millimetre, allowing for precise cutting. (after the Swiss -physician his results first. Many other famous Cuts made with Ho:YAG generally Philippe Plantamour), but uncertainties hail from the city including solution chemist self-cauterize, minimizing bleeding. In about the element’s identity lingered; (who studied under Thalén urology, Ho:YAG lasers are used for removal both he and Soret became embroiled in a and Cleve) and, of course, Alfred Nobel. of urinary stones4 and the treatment of an priority dispute with the American chemist Stockholm county boasts , the periodic enlarged prostate5. J. Lawrence Smith. Smith claimed to have table’s most-honoured suburb (namesake of 137 years after its discovery, holmium discovered the same element (he named it Y, Yb, Er and Tb), and the original source of languishes as one of the most underutilized mosandrum after , several elements, including holmium. elements on the . Although discoverer of three lanthanoids). The dispute Delafontaine later attempted to obtain a medical uses of Ho:YAG lasers account for fulminated in French-language journals1,2. purer sample of philippium, but holmium had an order of magnitude increase in mentions During this , already become elemental dogma. Modern in the scientific literature beginning in the in Uppsala, was analysing erbia- texts often acknowledge Delafontaine, late 1980s, holmium remains one of the containing residues from ’s Soret and Cleve for finding holmium, but least-discussed elements — perhaps some recent separation of from Thalén could share credit for the discovery fascinating holmium may yet ores. A spectroscopic analysis of erbia because Delafontaine and Soret also used be discovered6. ❐ (erbium ) by physicist Tobias Robert spectroscopy to identify the element. Thalén led Cleve to propose the presence of Holmium’s chemical similarity to its BRETT F. THORNTON is in the Department additional undiscovered elements in erbia, neighbouring elements made it difficult to of Geological Sciences, Stockholm and he went on to separate two new discover; today this similarity often leads to University, 106 91 Stockholm, Sweden. from a sample of it. A brown oxide he named few compelling reasons to select it for a given SHAWN C. BURDETTE is in the Department thulia (hence, ) and a green oxide purpose from a choice of other similar — of Chemistry and Biochemistry, Worcester holmia — the medieval Latin name for Cleve’s and often cheaper — lanthanoids. Holmium’s Polytechnic Institute, Worcester, hometown of Stockholm3. Because Cleve had high magnetic susceptibility means that it is Massachusetts 01609-2280, USA. more comprehensive and convincing data, occasionally used in high-strength , e-mail: [email protected]; Cleve’s claim gained precedence, and the new especially as a magnetic-flux concentrator; [email protected] element became known as holmium. however, elemental holmium’s magnetic Stockholm’s chemistry pedigree is properties only manifest themselves at References 1. Soret, J‑L. Arch. Sci. Phys. Nat. 13, 89–112 (1878). legendary. Berzelius worked in the city cryogenic . 2. Soret, J‑L. C. R. Hebd. Acad. Sci. 86, 1062–1064 (1878). and helped discover at least four elements Holmium is now commonly used in 3. Cleve, P. T. C. R. Hebd. Acad. Sci. 89, 478–480 (1879). (his students, including Mosander, found surgical lasers, where holmium-doped 4. Bagley, D. & Erhard, M. Tech. Urol. 1, 25–30 (1995). garnet (Ho:YAG) is the lasing 5. Elzayat, E. A., Habib, E. I. & Elhilali, M. M. Urology 66, 108–113 (2005). material, with an infrared emission around 6. Lin, J., Diefenbach, K., Cross, J. N., Babo, J‑M. & 2,100 nm. This wavelength is particularly Albrecht-Schmitt, T. E. Inorg. Chem. 52, 13278–13281 (2013). Gd Tb Dy Ho Er Tm Yb Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po 532 CHEMISTRY | VOL 7 | JUNE 2015 | www.nature.com/naturechemistry

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