Lutetium

Lutetium was named after the city of Paris because it was discovered by the Parisian chemist Georges Urbain, who was a professor at the Sorbonne. But it's not quite as simple as that.

Urbain found lutetium in the mineral ytterbia, which had been discovered in 1878 by the Swiss chemist Jean Charles Galissard de Marignac. Marignac had discovered ytterbia in a sample of gadolinite (a.k.a. ytterbite), which he'd found near the Swedish village of Ytterby. He suspected that ytterbia was a compound of a new element, which he called 'ytterbium'.

By 1907 ytterbium still had not been isolated, and three different scientists, working independently, discovered that ytterbia actually consisted of two different elements. Urbain was one of the three; the other two were the Austrian mineralogist Baron Carl Auer von Welsbach and the American chemist Charles James. Urbain named the elements neoytterbium and lutecium; Welsbach chose the names aldebaranium and cassiopeium (after the star Aldebaran and the constellation Cassiopeia).

It was a bitter dispute, with each claiming that the other had stolen his work. But Urbain was in the fortunate position that he was one of the three members of the International Commission on Atomic Weights, which was responsible at the time for the attribution of names to new elements. Needless to say, the Commission came down in favour of Urbain's names, except that neoytterbium reverted to ytterbium, and in 1949 the spelling of lutecium was changed to lutetium.

Urbain believed that he had discovered a third element in ytterbia. In 1911 he claimed that it was element no. 72, and he named it celtium. His fellow-chemists supported his claim, but the physicists argued that the new X-ray spectroscopy methods proved that Urbain's sample did not contain element 72.

(Wikipedia, rather confusingly to my mind, says that what Urbain called celtium was in fact pure lutetium. Its explanation is that "Welsbach's 1907 samples of lutetium had been pure, while Urbain's 1907 samples only contained traces of lutetium". Personally, I find the logic of this to be beyond me!)

Element 72 was eventually discovered in 1923 by the Dutch physicist Dirk Coster and the Hungarian Georg von Hevesy. They named it hafnium, from the Latin name for the city where they worked together: Copenhagen – which also happened to be the home town of Niels Bohr.

Urbain's claims in respect of element 72 did little credit to his work on lutetium, and some German-speaking chemists continued to refer to it as cassiopeium until the 1950s.