Wednesday, January 12, 2011

Carl Auer von Welsbach: The Rare Earth Kingdom’s Royal Surveyor?

As a well-renowned chemist and a discoverer of a number of rare earth elements, is Carl Auer von Welsbch the Rare Earth Kingdom’s Royal Surveyor?

By: Ringo Bones

Born in Vienna back in September 1, 1858, little did the whole world knew that Carl Auer von Welsbach will in a few years time be almost single-handedly exploring and surveying the then relatively unknown “Rare Earth Kingdom” in Mendeleyev’s Periodic Table for the benefit of not just the world of chemistry, but for all mankind. The exploratory journey started when Welsbach first studied chemistry under Robert W. Bunsen at the University of Heidelberg, where Welsbach made investigations in the chemistry of rare-earth metals. Later, Welsbach attended the University of Vienna.

In his exploration of the Rare Earth Kingdom, Welsbach became the first chemist to isolate the elements neodymium, samarium and praseodymium back in 1885. he is also best known for his invention in 1885 of the Welsbach Mantle – a means for increasing the illumination given off by a gas jet – which soon after found world-wide use. The Welsbach Mantle consisted of a wad of cotton which had been dipped in a salt solution of zirconium or some other suitable element. The mantle was supported over a gas jet, which would burn away the cotton the first time it was lit., leaving a brittle network of filament which becomes incandescent at a much lower temperature – thus making gas jet illumination much more fuel efficient.

During the advent of electric lighting, Welsbach invented the osmium filament for electric lights. And in 1907, Welsbach managed to isolate another rare earth element called lutetium to a reasonable degree of chemical purity back in 1907 before the advent of the post-World War II zeolite ion-exchange techniques. For a number of years, Welsbach was a member of technical societies in Vienna, Stockholm and Berlin. He died in Carinthia on August 4, 1929. Before passing away, Carl Auer von Welsbach managed to map much of the rare earth portion of the periodic table for the ease and convenience of a generation of chemists following his footsteps.


  1. Due to the safety concerns over the use of thorium in gas mantles - as thorium decays into radium-220 which could be easily inhaled by gaslight users and could result in lung cancer over prolonged exposure - newer models of Welsbach Mantles now use the rare earth metal yttrium or the transition metal zirconium as a substitute for thorium.

  2. For your information April Rain, yttrium is a First Transition metal with Rare Earth metal like chemical properties - i.e. a "lanthanoid". You might be referring to cerium replacing thorium in gaslight mantles. Radium-220 emission is also a concern in some homes and public buildings for some time now in the US. The famed Grand Central Station's granite slabs emit radium-220 with much higher background radiation readings than the typical radiation readings reception lobby in a typical commercial nuclear fission power pant.

  3. Even the humble relatively low-tech gaslight mantle or Welsbach Mantle is now affected by the current rare earth shortage.

  4. Given that the People's Republic of China already produces most f the gas mantles sold all over the world, replacing thorium with a safer rare earth substitute would surely be a piece of cake, right?

  5. The modern thorium-free gas mantle was invented by Carl Auer von Welsbach called Actinophor which he patented back in 1885. It consisted of 20% magnesium oxide, 20% lanthanum oxide and 20% yttrium oxide.