New element named for discoverer of X-rays

By Associate Professor Allan Blackman

This article was orignally published in the Otago Daily Times on Monday 2 August 2004.

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Groucho Marx once famously said that he would not want to belong to any club that would accept him as a member. Yet even he would be hard-pressed to decline membership of a club which would guarantee one absolute immortality. Such a chemical club does exist. At present, it has only 13 members — and it is soon to get one more.

The names of Vasilii Yefrafovich von Samarski-Bykhovets (Samarium), Johan Gadolin (Gadolinium), Pierre and Marie Curie (Curium), Albert Einstein (Einsteinium), Enrico Fermi (Fermium), Dmitri Mendeleev (Mendelevium), Alfred Nobel (Nobelium), Ernest Lawrence (Lawrencium), Ernest Rutherford (Rutherfordium), Glenn Seaborg (Seaborgium), Niels Bohr (Bohrium) and Lise Meitner (Meitnerium) are the only ones to have been immortalised on the Periodic Table of the Elements, and, while you might not have heard of many of them, all except the first were giants in the fields of either chemistry or physics (Samarski-Bykhovets was the chief of staff of the Russian Corps of Mining Engineers). And soon to be added to these illustrious names is that of Wilhelm Roentgen, the discoverer of X-rays.

Chemical elements are the fundamental building blocks of all matter, and each consists of only a single type of atom. Thus hydrogen, nitrogen and oxygen are elements, as they consist of only hydrogen, nitrogen and oxygen atoms respectively, while water, being made up of both hydrogen and oxygen atoms, is not an element.

There are 116 known chemical elements, the two most recent having been reported earlier this year, and these are listed in numerical order on the Periodic Table of the Elements. The discoverer of any new element gets to suggest a name for it, and recently it has been customary to name new elements after either famous scientists, or places where the elements were discovered. As it usually takes quite some time to confirm these discoveries, there is often a significant gap between the isolation of a new element and its naming. Element 111 was discovered in 1994, and only this year has it been confirmed as a genuine new element. Thus, in May, the name Roentgenium (symbol Rg) was proposed for this element, and it is most appropriate that Roentgen be so honoured.

Wilhelm Roentgen was the first winner of the Nobel Prize for Physics in 1901, for his discovery of X-rays on the evening of November 8, 1895. As has been the case in many great scientific discoveries, the breakthrough came about accidentally, while he was investigating the passage of electric current through very low pressure gases. He immediately recognised the possible uses of these new rays, and by December 22, he had obtained the very first X-ray image of a human, a picture of his wife's hand shown in the accompanying figure. Amazingly, to us in this day and age, Roentgen chose not to patent his discovery, which would surely have been worth a vast amount of money to him, and he apparently even refused to have X-rays named after him.

While you can all appreciate the medical uses of X-rays, you might not perhaps realise the importance of X-rays in chemistry. The technique of X-ray crystallography involves firing X-rays at a crystal of the material to be studied, and allows us to see how individual atoms are arranged within a molecule, to an accuracy of at least a billionth of a millimetre. For this reason alone, Roentgen is thoroughly deserving of his everlasting place on the Periodic Table of the Elements.

And speaking of the periodic table, if you want to see how well a certain TV celebrity knows the first 20 elements, be watching TV2 at 5:30pm on Wednesday.