Friday, 23 March 2012

Georges Urbain

Who is Georges Urbain ?

How does Georges Urbain fit in with the number 72 ?

He was born in 1872 in Paris and became a top notch chemist and a Professor. Urbain had a passion for the arts and loved to paint, sculpt, and play music.

As a professional chemist he understood the existing atomic elements of the periodic table introduced by Mendeleev back in the 1800's. Georges Urbain and Baron Carl Auer von Welsbach are credited with co-discovering the element lutelium. Charles James is also associated to the isolation of this rare earth element.

Lutelium is a pure metal and belongs in space 71 of the periodic table of elements. It is also 71Lu.

Georges Urbain was the one who seperated lutetium from ytterbia ( yttterbium oxide ) in 1907.

Georges Urbain thought he had found element 72 also in 1907 and reported it to the scientific community as a rare earth metal. In his report in 2011 he called atomic number 72 Celtium. The scientific community tested out his claim and found that the spectra and chemical behaviour the Celtium did not match the true characteristics of an element that should fill in the 72 space. Hafnium discovered in 1923 fit that character. The scientists of this era were shifting from old school mineral analysis models to state of the art instruments like those used by Moseley when he was using X-ray spectroscopy to measure wavelengths. Not all scientists of this era trusted the new technology and the controversy over Celtium being element 72 dragged on for several years.

Georges Urbain taught thermodynamics at Sorbonne University in Paris.

One hundred and twenty years ago Georges Urbain was born, in Paris, on 12th
April. He was educated in Paris and graduated, as top student, in 1894. He obtained a DSc
iri 1898 with a thesis on the RE elements and from the same year to 1904 worked in
industry. He then followed his true vocation as a teacher, finally becoming professor of
chemistry at the Sorbonne, in 1908. His main research interests were in the field of RE
chemistry and he is best known for his discovery of lutecium and for his unsuccessful
attempts at isolating another RE metal which he hoped to call celtium. It was during these
researches that, in 1912 (three years before Honda’s landmark publication on
thermogravimetry) he converted an analytical balance into a thermobalance in order to
study materials which decomposed at a perceptible rate, with the evolution of a gas. He
established a law governing the efflorescence of hydrates in a dry atmosphere, carried out a few experiments on EGA but soon lost interest in thermogravimetry. - tmg newsletter


Bohr and others who play a role in the isolation of element 72.

Resource - Hafnium

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