Nyholm, Ronald Sydney (1917–1971)

Australian inorganic chemist who worked on the coordination compounds (complexes) of the transition metals. He was knighted in 1967.

Nyholm was born in Broken Hill, New South Wales, and studied at Sydney and, after World War II, at University College, London, where he became professor 1955. As chair of the Chemistry Consultative Committee, he was largely responsible for the Nuffield chemistry course taught in British schools and for changes to the examination syllabuses. He advocated an integrated approach to the teaching of chemistry.

Nyholm was able to prepare stable compounds of transition metals in valence states that previously had been thought to be unstable. For example, he prepared an octahedral complex of nickel(III), in which the nickel has a coordination number of six. He also made the diarsine complexes of the tetrachloride and tetrabromide of titanium(IV), the first example of an 8-coordination compound of a first-row transition metal.

Nyholm systematically exploited physical methods to study the structures and properties of coordination compounds. He employed X-ray crystallography and nuclear magnetic resonance spectroscopy, and found that magnetic moment seemed to give the closest connection between electronic structure, chemical structure, and stereochemistry.