Ernest Gordon Cox (1906-1996)

J. Appl. Cryst. (1997). 30, 208-208

Sir Ernest Gordon Cox FRS died on 23 June 1996 at the age of 90. His career as a practising crystallographer lasted from 1927, when he joined Sir William Bragg's group at the Royal Institution, to 1960, when he left the University of Leeds to become Secretary of the UK Agricultural Research Council.

Cox graduated in physics at Bristol University. At the Royal Institution, Sir William Bragg suggested as his main task the crystalline structure of benzene. Even at 273 K the vapour pressure of benzene is very high. A special rotation camera, with a double-walled cylinder through which the cooling liquid was circulated, was constructed by C. J. Jenkinson the laboratory mechanic. X-ray measurements were made at 251 K. Cox showed that the evidence strongly favoured a flat-ring molecule with C - C about 1.42 Angstrom.

In 1929 he was recruited by W. N. Haworth, the carbohydrate chemist, to the staff of the Chemistry Department of Birmingham University. Here he did pioneer work on the structures of sugars and coordination compounds of nickel, palladium, platinum and other metals. A highlight was the determination of the crystal structure of vitamin C, ascorbic acid, where his X-ray work was done in concert with the chemists. (Haworth received the Nobel Prize in 1937 for his investigations on carbohydrates and vitamin C.) Cox became increasingly interested in the determination of accurate structures from three-dimensional data. Pentaerythritol (1937) was followed by glucosamine hydrobromide (1939).

After scientific and military service in the Second World War, he was appointed in 1945 as one of the Professors of Chemistry at Leeds. There he built a very happy Department of Inorganic and Structural Chemistry and a strong all-round group in chemical crystallography. Based on his Birmingham experience, Cox was keenly aware that good results in chemical crystallography were dependent on developments in apparatus and computing. In the first years in Leeds, he took a particular interest in the design and production of a Weissenberg camera and in the use of Hollerith punched-card equipment. He was very quickly aware of the potentialities of electronic computers, and despatched one of his team to the first programming school at Cambridge in 1950, and thereafter to exploit the Ferranti Mark I machine in Manchester from 1952 onwards. The benzene story was completed by placing the crystallographer as well as the crystal inside a cold room. It led to the discovery of the librational correction to atomic positions (1955).

A stream of high-grade structure determinations flowed from his team, often setting standards for others to follow. Many analyses concerned relatively simple molecules, such as heterocyclic sulfur compounds, with the object of establishing reliable values for standard bonds. The work on stereochemistry of coordination compounds was considerably broadened, e.g. to include new organic compounds of platinum. Low-temperature work was extended down to 34 K. Cox led the bid for an ICL Pegasus computer for the University of Leeds. When it was installed in 1957, his crystallographers were immediately the largest users.

His administrative skills and good sense drew him increasingly into the general running of the university and onto outside committees. He was a member of the IUCr Commission on Crystallographic Apparatus from 1948-1957 and of the Commission on Crystallographic Data from 1954-1960. He was Chairman of the X-ray Analysis Group, the main precursor of the British Crystallographic Association, from 1956 to 1959.

He was a member of the national Agricultural Research Council from 1957-1960. This led to his departure from Leeds in 1960, when he was appointed Secretary (i.e. chief executive) of the ARC. He retired from this post in 1971. An especially moving tribute to his work there was paid by the politician Tam Dalyell MP in The Independent newspaper of 8 July 1996 - `Never was there a more impressive, energetic advocate of the value to society of long-term serious scientific inquiry'.

Durward Cruickshank