RALPH W. G. WYCKOFF (1897 - 1994). The Analytical Expression of the Results of the Theory of Space Groups. Washington: Carnegie Institution, 1922.
WILLIAM T. ASTBURY (1898 - 1961) and KATHLEEN YARDLEY [LONSDALE] (1903 - 1971). Tabulated Data for the Examination of the 230 Space-Groups by Homogeneous X-Rays. (Philosophical Transactions of the Royal Society of London, 1924, A224, 221-257).
Wyckoff was born on 9 August 1897 in Geneva, New York, and obtained his Ph.D. at Cornell University for a thesis on X-ray diffraction. Wyckoff then joined the Geophysical Laboratory in Washington D.C., where he carried out fruitful research on the crystal structures of minerals of high symmetry.
From 1927 until 1937, Wyckoff worked at the Rockefeller Institute for Medical Research and then moved to industry, where he developed the first vaccine against epidemic typhus fever, and a dried blood plasma formulation for in-field use by the armed forces. Later at the University of Michigan, he began to use electron microscopy to take beautiful three-dimensional images of viruses.
In the course of his work at the Geophysical Laboratory, Wyckoff found that the classification of crystals according to space-group theory of E. S. Fedorov and Arthur Schoenflies was a powerful tool. In order to streamline his work, he prepared a set of tables with specific information about the locations of symmetry-related points for each of the 230 space groups. These tables formed the basis of his 1922 book, and the different symmetry-related points in any particular space group are still called Wyckoff positions to this day.
Wyckoff's book inspired Astbury and Yardley (see below under her married name Kathleen Lonsdale), who were both working in William H. Bragg's laboratory at University College, London, to write a paper in which the locations of symmetry-related points were represented in a novel graphical form. Their article, published in the Philosophical Transactions in 1924, made the job of understanding the symmetry properties of crystals much easier, and crystallographers around the world used it extensively. Their approach is still used today, as embodied in the reference volumes entitled the International Tables of Crystallography.
Jan Drenth and Aafje Looyenga-Vos, "Ralph W. G. Wyckoff," Acta Crystallographica 1995, A51, 649-650.
Complete Dictionary of Scientific Biography. Detroit: Charles Scribner's Sons, 2008, v1, p319-320.
Complete Dictionary of Scientific Biography. Detroit: Charles Scribner's Sons, 2008, v8, p484-486.