Bury, Charles Rugeley
BURY, CHARLES RUGELEY
(b. Henley-on-Thames, England, 29 July 1890: d. Chichester, England, 30 December 1968)
Bury was the eldest of the five children of a solicitor. Although the family lived in Gloucestershire, he spent much time with a grandmother at Leamington. After graduating from Malvern College in 1908. he won a scholarship to Trinity College, Oxford, where his tutor was D. H. Nagel and his research supervisor in electrochemistry was Harold Hartley. In 1912 Bury graduated from Oxford with first-class honors. He then spent six months at Göttingen in the period 1912–1913.
His appointment as assistant lecturer in chemistry at University College of Wales, Aberystwyth (1913), was interrupted when Bury volunteered in August 1914 and served on the western front and in Mesopotamia; later, as a captain, he led troops through Iran to the Caspian Sea. In 1919 he returned to Aberystwyth, where he remained until 1943, At I.C.I. Billingham, Bury led a phase rule group from 1943 until 1952. In 1922 he had married Margaret Adams, an agricultural botanist. They had a son and a daughter.
Bury’s first paper (1921) is an exceptional achievement. Its contents provide the basis of what is taught to college chemistry students as the interpretation of the periodic table in terms of the electronic structure of the atoms, This lucid statement was for many years overlooked because of a common assumption that Niels Bohr was responsible for it. In the same year Bohr published a communication in which he stated:’ The application of the correspondence principle… suggests that after the first two electrons are bound in one-quantum orbits, the next eight electrons will be bound in two-quanta orbits, the next eighteen in three-quanta orbits and the next thirty-two in four-quanta orbits.’ For the atoms of the inert gases he proposed the following constitutions: helium (21), neon (2182), argon (218282), krypton (21 8218382), xenon (218218318382), [niton] (218218332418382). He went on to say that in the rare earths we may assume the successive formation of an inner group of thirty-two electrons and, similarly, that we may suppose that the appearances of the iron, palladium, and platinum families are witnessing stages in the formation of groups of eighteen electrons. Bohr’s letter leads one to conclude that he arrived at the inert gas structures largely by intuitive insight.
Bury submitted his paper some three weeks after Bohr’s letter appeared. He wrote,’ During the course of preparation of this paper, structures similar to those suggested by the author for the inert gases have been proposed by Bohr.’ He expressed his own views thus:
Successive layers can contain 2, 8, 18. and 32 electrons. Groups of 8 and 18 electrons in a layer are stable, even when that layer can contain a larger number of electrons. The maximum number of electrons in the outer layer of an atom is 8: more than 8 electrons can exist in a shell only when there is an accumulation of electrons in an outer layer. During the change of an inner layer… there occurs a transition series of elements which can have more than one structure.
On these bases Bury summarizes in seven pages the valence properties of all elements up to uranium, accounting for the atomic numbers of transition elements and rare earth elements. The latter he correctly starts with cerium and finishes with lutecium. Apart from essential features reproduced in introductory accounts of the chemical elements, there are two special details.
First, Bury states: “Between lutecium and tantalum an element of atomic number 72 is to be expected. This would have the structure (2,8,18,32,8,4) and would resemble zirconium’ (emphasis added). In January 1923 Dirk Coster and Gyorgy von Hevesy reported their identification of hafnium (atomic number 72) in zirconium minerals. Hevesy, Mary E. Weeks, and others who recount the history of the discovery of hafnium 60 not mention Bury but give credit to Bohr, whose first mention of element 72 only follows after Bury, Later, Bohr acknowledged Bury”s priority.
Second, under the heading “The Last Period,” Bury writes:
In this period a second 18–32 transition series may be expected…. Little resemblance [between the actinides and lanthanides]… is to be expected Possibly an element, not yet discovered, of atomic number 94… is the first of a series of 7 transition elements… something like the ruthenium group but more electropositive.
These comments are perhaps the first reasoned predictions on transuranic chemistry.
Bury had mathematical inclinations and a very clear grasp of thermodynamics. He used partial molar values to study the state of solute molecules. In the early 1920’s McBain postulated multimolecular aggregates in soap solutions where Bury anticipated complications from hydrolysis. Bury established and first explained the critical concentration for micelle formation in aqueous solutions of butyric acid:
where K is the Haber form of the constant and n is the number of molecules in a micelle. As [A1] = monomer concentration exceeds K a very rapid increase in [An] occurs, Bury followed such molecular aggregations by freezing point, specific heat, density, conductivity, and viscosity measurements.
In 1935 Bury wrote another seminal paper, in which he related the appearance of color in nearly all the well-known families of organic dyestuffs to the presence of resonance (as electronic delocalization was described) between two often strictly equivalent molecular electronic structures, for instance, in Dobner’s violet:
In three pages he offers equivalent formulations for fifteen dyestuff families. Surprisingly, he instances indigo as a noncomplier (Kuhn had anticipated him in this instance). Bury did not know of Kuhn’s paper.
G. N. Lewis and Melvin Calvin conducted extended studies in this area. Others who immediately used Bury’s indications on dyestuff structures included Schwarzenbach, Hamer and Mills, and L. G. S. Brooker.
BIBLIOGRAPHY
I. Original Works. Bury’s writings include’ ’Lang muir’s Theory of the Arrangement of Electrons in Molecules and Atoms,’ in Journal of the American Chemical Society, 43 (1921) 1602–1609; The Densities of Butyric Acid-Water Mixtures,’ in Journal of the Chemical Society (London) (1929). pt. 1. 679–684, written with John Grindley; “The Electrical Conductivity of Butyric Acid-Water Mix tures,’ ibid. (1930), pt. 2, 1665–1668. written with John Grindley:’ The Partial Specific Volume of Postassium n Octate in Aqueous Solution,’ ibid., 2263–2267, written with D.Gwynne Davies;’ Auxochromes and Resonance,’ in Journal of the American Chemical Society, 57 (1935) 2115–2117; and’ The Duhem-Margules Equation and Raoult’s Law,’ in Transactions of the Faraday Society, 36 (1940), 795–797.
II. Secondary Literature. Biographical notices are Mansel Davies,’ C. R. Bury: His Contributions to Physical Chemistry,’ in Journal of Chemical Education, 63 (1986). 741–743. and’ Charles Rugeley Bury and His Contributions to Physical Chemistry,’ in Archive for History of Exact Sciences, 36 (1986), 75–90.
Mansel Davies