Hugo M. Rietveld (7 March 1932 – 16 July 2016) was a Dutch crystallographer and one of the most prominent crystallographers of the 20th century. He is famous for his invention of the Rietveld refinement method, which is used for the characterisation of crystalline materials from powder diffraction data. The Rietveld refinement uses a least squares approach to refine a theoretical line profile (calculated from a known or postulated crystal structure) until it matches the measured profile. The introduction of this technique was a significant step forward in the diffraction analysis of powder samples.
After completing Grammar School in the Netherlands he moved to Australia and studied physics at the University of Western Australia in Perth. In 1964 he obtained his PhD degree with a thesis entitled "The Structure of p-Diphenylbenzene and Other Compounds", a single crystal neutron and X-ray diffraction study. This investigation was the first single crystal neutron diffraction study in Australia and was conducted at the nuclear reactor, HIFAR, in Sydney.
In 1964 he became a research officer at the Netherlands Energy Research Foundation ECN in Petten, and was mainly involved in neutron powder diffraction studies of uranates and other ceramic compounds.
After a scientific and managerial career with ECN he retired in 1992.
- The Royal Swedish Academy of Sciences awarded Hugo M. Rietveld, the Aminoff prize in Stockholm, 31 March 1995.
- Barrett Award on behalf of the Denver X-ray Conference Organizing Committee in Denver, U.S., 6 August 2003.
- The Royal Award of Officer in the Order of Oranje-Nassau, for his outstanding contribution to the field of chemistry. Alkmaar, Netherlands, 28 October 2004.
- Award for Distinguished Powder Diffractionists, awarded by The European Diffraction Conferences, handed out on 30 August 2010 in Darmstadt.
- Hans-Kühl-Medal 2010, awarded by Gesellschaft Deutscher Chemiker (GDCh), Fachgruppe Bauchemie, handed out on 7 October 2010 in Dortmund.