Carl Auer von Welsbach

Carl Auer was born in Vienna on 1 September 1858 to Alois Auer and his wife, Therese Neuditschka. He was the youngest of four children, his elder siblings being Leopoldine, Alois and Amalie. His father, ennobled in 1860 (as Alois Ritter Auer von Welsbach), was director of the Imperial printing office (K.-k. Hof- und Staatsdruckerei) in the days of the Austrian Empire. Next, he joined the Austro-Hungarian Army for one year of voluntary military service. He was commissioned as a Second Lieutenant. He joined on October 1, 1877, and received his patent as a lieutenant on December 15, 1878. In 1878, Auer entered the University of Vienna, studying mathematics, general chemistry, engineering physics, and thermodynamics. He then moved to the University of Heidelberg in 1880, where he continued his studies in spectroscopy under the direction of Robert Bunsen, (inventor of the Bunsen burner). In 1882, he received his Ph.D. degree and returned to Vienna to work as an unpaid assistant in Professor Adolf Lieben's laboratory, working with chemical separation methods for investigations on rare-earth elements. == Rare earths ==

Neodymium and praseodymium File:Neodymium (60 Nd).jpg|Purified neodymium File:Praseodymium.jpg|Purified praseodymium In 1885, Auer von Welsbach used a method of fractional crystallization that he had developed himself to separate the alloy didymium into its two parts, for the first time. It had previously been believed to be an element. After 167 crystallizations, Auer von Welsbach differentiated it into two colored salts: he named the green colored salt "praseodymium" and the pink one "neodidymium". He announced his achievement to the Vienna Academy of Sciences on 18 June 1885. His achievement was approved by Bunsen, but met with considerable skepticism from others. The name "neodidymium" is derived from the Greek words neos (νέος), new, and didymos (διδύμος), twin. The name praseodymium comes from the Greek prasinos (πράσινος), meaning "green". In naming both elements, and not leaving the original name didymium to the more-abundant component, Auer von Welsbach diverged from established practice, which was to give a new name only to the less-abundant component. Nonetheless, his name for the major fraction, neodidymium, after some modification, became the name of the element neodymium. Praseodymium was also accepted as the name of the minor fraction. Lutetium and ytterbium File:Ytterbium.jpg|Ytterbium File:Lutetium sublimed dendritic and 1cm3 cube.jpg|Purified lutetium The rare earth element lutetium was independently discovered by three scientists at around the same time in 1907: French scientist Georges Urbain, Austrian Auer von Welsbach, and American Charles James. All three were successful in separating the substance then known as ytterbium into two new fractions. To name the newly discovered fraction, Urbain suggested the name "lutecium", for the Roman city of Lutetia that preceded Paris. Auer von Welsbach suggested the name "cassiopeium". James' work was not yet published when the others' work appeared, and he did not involve himself in subsequent disputes. Lutetium, a slight modification of Urbain's name, was eventually accepted after a long battle between Urbain and Welsbach. ==Lighting innovations==

Gas mantle burning at full brightness On 23 September 1885, Auer von Welsbach received a patent on his development of the gas mantle, which he called Auerlicht, using a chemical mixture of 60% magnesium oxide, 20% lanthanum oxide and 20% yttrium oxide, which he called Actinophor. A lawsuit (Wagner v. Coleman) was brought against Coleman. The company changed its formulation to use non-radioactive materials, which apparently cost less and last longer. Metal-filament light bulb Auer von Welsbach then started work on development of metal-filament mantles, first with platinum wiring, and then osmium. Osmium is very difficult to work with, but he developed a new method, which mixed osmium oxide powder with rubber or sugar into a paste, which is then squeezed through a nozzle and fired. The paste burns away, leaving a fine wire of osmium. Welsbach's flints consisted of pyrophoric alloys, 70% cerium and 30% iron, which when scratched or struck would give off sparks. This system remains in wide use in cigarette lighters today. In 1907 he formed Treibacher Chemische Werke GesmbH to build and market the devices. ==Radium research==

For the rest of his life Auer von Welsbach turned again to "pure" chemistry. He worked largely on his estate at Welsbach Castle (Schloß Welsbach) near Treibach near Althofen. Between 1907 and 1918, Auer von Welsbach focused on isolating preparations of actinium and thorium as by-products of radium extraction. He presented a major paper on his spectroscopic work and the separation of radioactive elements in 1922. The following photographs show scientific equipment from Auer von Welsbach's laboratory, from "Spektroskopische Methoden der analytischen Chemie" (1922). File:Welsbach Figure 1 spektroskopische-lytischen-chemie-18.pdf| Figure I, Early version of spark apparatus File:Welsbach Figure II spektroskopische-lytischen-chemie-19.pdf| Figure II, Later version of spark apparatus File:Welsbach Figure III spektroskopische-lytischen-chemie-20.pdf| Figure III File:Welsbach Figure IV spektroskopische-lytischen-chemie-21.pdf| Figure IV, Spectral comparison panel in very reduced scale File:Welsbach Figure V spektroskopische-lytischen-chemie-22.pdf| Figure V, Comparative apparatus for spectra == Commemoration ==

, niobium and silver. In 2008 (150 years after his birth), Auer von Welsbach was selected as a main motif for a high-value collectors' coin: the Austrian €25 Fascination Light. He was also depicted on postage stamps of 1936, 1954 and 2012. ==Awards and honors==

• 1900, Elliott Cresson Medal, The Franklin Institute Awards, Philadelphia, PA, USA • 1901, raised to the hereditary nobility by Franz Joseph I of Austria, with the title of Freiherr Auer von Welsbach • 1920, Werner von Siemens Ring • 1921, Wilhelm Exner Medal, inaugural awardee, Austrian Industry Association, Austria • 1988, the Welsbach Museum at Althofen was opened in April, 1998 • 2011, National Inventors Hall of Fame, North Canton, Ohio, USA == See also ==