Posts Tagged ‘Niels Bohr’
Monday, May 20th, 2013
Sometimes the originators of seminal theories in chemistry write a personal and anecdotal account of their work. Niels Bohr[1] was one such and four decades later Robert Woodward wrote “The conservation of orbital symmetry” (Chem. Soc. Special Publications (Aromaticity), 1967, 21, 217-249; it is not online and so no doi can be given). Much interesting chemistry is described there, but (like Bohr in his article), Woodward lists no citations at the end, merely giving attributions by name. Thus the following chemistry (p 236 of this article) is attributed to a Professor Fonken, and goes as follows (excluding the structure in red):
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References
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N. Bohr, "Der Bau der Atome und die physikalischen und chemischen Eigenschaften der Elemente", Zeitschrift f�r Physik, vol. 9, pp. 1-67, 1922. http://dx.doi.org/10.1007/BF01326955
Tags:electrocyclic, energy, final product, free energy, Gerhard Fonken, Historical, Niels Bohr, pericyclic, professor, Reaction Mechanism, Robert Woodward, Woodward
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Sunday, June 5th, 2011
In 1923, Coster and von Hevesy[1] claimed discovery of the element Hafnium, atomic number 72 (latin Hafnia, meaning Copenhagen, where the authors worked) on the basis of six lines in its X-ray spectrum. The debate had long raged as to whether (undiscovered) element 72 belonged to the rare-earth group 3 of the periodic table below yttrium, or whether it should be placed in group 4 below zirconium. Establishing its chemical properties finally placed it in group 4. Why is this apparently arcane and obscure re-assignment historically significant? Because, in June 1922, in Göttingen, Niels Bohr had given a famous series of lectures now known as the Bohr Festspiele on the topic of his electron shell theory of the atom. Prior to giving these lectures he had submitted his collected thoughts in January 1922[2].
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References
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D. COSTER, and G. HEVESY, "On the Missing Element of Atomic Number 72", Nature, vol. 111, pp. 79-79, 1923. http://dx.doi.org/10.1038/111079a0
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N. Bohr, "Der Bau der Atome und die physikalischen und chemischen Eigenschaften der Elemente", Zeitschrift f�r Physik, vol. 9, pp. 1-67, 1922. http://dx.doi.org/10.1007/BF01326955
Tags:Bohr, Bury, chemical bonding, Chemical IT, chemical properties, Copenhagen, General, green technologies, Hafnium, Historical, Langmuir, Niels Bohr, silicon chips, Technetium, X-ray
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