Henk was a very amiable, good-natured crystallographer who meant a lot to the Dutch and International crystallographic community.
Henk, born in Koog aan de Zaan, studied chemistry at the University of Amsterdam (UvA) and learned crystallography from Caroline MacGillavry, with whom he also obtained his PhD with the thesis ‘Automation of the symbolic addition method: Application to some compounds from the vitamin-A chemistry’. The ‘Direct Method’ program SIMPEL was further developed and later the so-called ‘quartets’ and ‘quintets’ were added.
Henk became a personally appointed professor of ‘Direct Methods in Crystallography’ at the UvA in 1980. He gathered around him a large group of students from the Netherlands and abroad, all of whom enjoyed the academic freedom that was given to them. In 1988, the chair of Chemical Crystallography was established and assigned to Henk. He held this position until his retirement in 2004.
In addition to his numerous scientific publications, Henk held numerous additional (administrative) positions such as president of the International Union of Crystallography (IUCr, 1999-2002), president of the Dutch Chemical Society (KNCV) and the Dutch fundamental research community for Crystal and Structural Research as well as dean of the UvA. On March 30, 1990, he founded, together with Roeli Olthof-Hazekamp, the Dutch Society for Crystallography.
Henk was a true citizen of the Zaanstreek, the industry area north of Amsterdam: straightforward and he loathed injustice. When Rietveld received all the credit for the “profile method” now called the Rietveld method, he, and Bob van Laar published an article in Acta A about the true origin of this method. Henk advocated referring in the future to the Loopstra and Rietveld article and calling the method the “Loopstra method” as a tribute to the inventor of the method.
We lose with Henk a colorful and inspiring crystallographer and wish his family much strength with this loss.
The original text of this obituary was published on the website of the NVK. Republished with permission from NVK.