Ralph W. G. Wyckoff (1897- 1994)

Ralph W. G. Wyckoff

On November 3 1994, Ralph Walter Graystone Wyckoff died at the age of 97. He published more than 400 papers, the first of which appeared when he was 19. He was employed in no less than eleven labs of very different types. His greatest strength was to apply new techniques or use new instruments, when they became available, in an intelligent way. In this way he became famous in two areas of structural research: X-ray diffraction and electron microscopy.

Ralph was born on August 9, 1897 in Geneva, NY, USA as the son of the judge Abram Ralph Wyckoff and Ethel Agnes (nee Catchpole) Wyckoff. His father descended from Dutch immigrants who arrived in America in 1634. His mother was born in England and went to the USA around 1880. Although left-handed by nature, the tough discipline at school forced him to write with his right hand. This made him able to use both hands easily, an advantage in his later experimental work. His scientific career started at Hoban College in Geneva where he wrote his first paper and published it in the Journal of the American Chemical Society in 1916.

That year Ralph moved to Cornell University in Ithaca intending to study astronomy. Because the war had depleted the Astronomy Department of its faculty, he decided to read chemistry instead. Influenced by the Japanese crystallographer S. Nishikawa, who spent a couple of years in the Physics Department of Cornell, Wyckoff started to work on X-ray diffraction, with Nishikawa as supervisor. The subjects of his thesis in 1919 were the structures of NaNO₃ and CsICl₂. The linear and symmetric structure of the [Cl-I-Cl] ion pointed to an unknown type of bond, which held the interest of structural chemists for many years.

After his graduation, a period of fruitful structural research on minerals with high symmetry followed in the Geophysical Lab in Washington (DC). Wyckoff collected X-ray diffraction data from multi-wavelength Laue and powder patterns. The classification of compounds into structure types according to Schoenflies' space-group theory played an important role in his structure determinations. The one or two parameters not determined by symmetry were roughly estimated from the relative intensities of a small number of reflections. This was in striking contrast to the procedure then used by the British crystallographers. They followed the Braggs, used monochromatic radiation and regarded quantitative intensity measurements as essential. However, they tended to underestimate the value of a systematic structural theory. This controversy disappeared when the study of more complicated structures required both accurate intensities and knowledge of the space groups.

"The Analytical Expression of the Results of the Theory of Space Groups", published by Wyckoff in 1922, contained tables with the positional coordinates, both general and special, permitted by the symmetry elements. This book formed the prelude to the description of the 230 space groups in the International Tables for X-ray Crystallography, the first edition of which appeared in 1935. In 1924, Wyckoff prepared another book, The Structure of Crystals, the first in a series of compilations of X-ray structural work.

In 1927, Wyckoff moved to the Rockefeller Institute for Medical Research, where he constructed an X-ray spectrometer with an ionization counter and used the instrument to determine the structure of urea and collect data for the amino acid glycine with the  ultimate goal of studying proteins. When the Rockefeller Institute abandoned its interest in X-ray crystallography, Wyckoff used his instruments to measure the effect of X-rays on living cells and undertook the construction of an ultracentrifuge of improved design for the isolation and purification of proteins and viruses. Beginning in 1937, he worked in industrial labs interested in a virus which was killing thousands of horses in the western United States. The purification of this virus led to the production of a successful vaccine. During the Second World War, Wyckoff produced a vaccine against epidemic typhus fever and dried blood plasma for infield use by the armed forces. In 1943, he was offered joint positions at the University of Michigan and the Michigan State Department of Health. He was not completely happy in Ann Arbor until he found an unused electron microscope in the basement of the Bacteriology Laboratory and succeeded in taking beautiful pictures of the influenza virus. They were especially appealing because of the metal shadowing technique, which provided a three-dimensional image. This success landed him a position at the National Institutes of Health in Bethesda. There, he spent happy and fruitful years (1946 to 1952) studying viruses and macromolecules. He was asked to show his impressive pictures at a meeting of European crystallographers in London (UK). Here, as a prominent American crystallographer, he became engaged in the foundation of what in 1948 would become the International Union of Crystallography, of which he was Vice-president and President from 1951 to 1957. He was also President of the American Crystallographic Association in 1951. In the post-war period, Wyckoff was mainly engaged in electron microscopy and in organizational activities in crystallography. He was a scientific attache at the American embassy in London for a period of two years. Even there he continued his electron microscopy research on a modest scale with an instrument provided by the Philips Company.

In 1960 he moved to the University of Arizona in Tucson to become a Professor in physics and microbiology. He focused his interest on fossils, which he studied with the electron microscope and by chemical analysis. When the rules of the University forced his retirement, he was already over 80 years old. He continued to work with a copper mining company, until he was 88 and spent the remaining years of his life in California.

Ralph Wyckoff had enormous energy. He did not obey official working hours; one could often find him at his microscope at 6 o'clock in the morning or at 2 o'c1ock at night. He had a deep interest in politics and in cultural matters, and loved classical music. He enjoyed travelling, especially in Europe. Many honours and honorary positions were bestowed on him and he was a member of several prominent scientific institutions.

We thank Eelco H. Wiebenga for personal information and Mike H. Dacombe for improving the language.