BY MARK G. INGHRAM

FREDERIK WILLIAM HOLDER ZACHARIASEN's contributions to science have been rich and varied. He was a leader in the determination of the crystal structure of inorganic crystals using x-ray diffraction. Though primarily an experimentalist, he contributed to theory whenever he found the theory inadequate. In over 200 published papers he included experiments on the crystal structure of minerals, on the structure of inorganic crystals, on the structure of anionic groups, on atomic and ionic radii, on the glassy state, on the liquid state, on actinide crystal chemistry, on high-pressure phases, on crystal structure and superconductivity, on the melting process, and on the variation of bond strengths with bond lengths. His contributions to theory include papers on temperature diffuse scattering of x-rays, on stacking disorder, on the phase problem, and on extinction including the Borrmann effect. Each of these theoretical efforts was followed by careful experimental investigations to establish the correctness of the theory he had developed.

Linus C. Pauling of the University of California at Berkeley, who also concentrated on the determination of crystal structure during his early years, said of Zachariasen's work (1975), ''I feel that he is to be classed among the outstand-