1. International Year of Crystallography 2014
Solid materials in the crystalline state are characterized by a periodic structure, which acts as a diffraction grating at an atomic scale for incident X-rays. The famous experiment of X-ray diffraction, using a zincblende crystal, was suggested by Max von Laue at the University of Munich, Germany and was conducted by W. Friedrich and P. Knipping in 1912. The Nobel Prize in Physics was awarded to Max von Laue in 1914 for his discovery of the X-ray diffraction phenomena, which verified the wave nature of X-rays. Discovery of X-ray diffraction changed the field of mathematical crystallography in the 19th century to an experimental science.
X-ray crystal structure analysis is a reverse process of X-ray diffraction. Intensities at individual diffraction spots recorded on the surface of a detector in reciprocal space are converted into their frequencies, and then inversely Fourier transformed into the crystal structure in real space. The X-ray diffraction method provides us the information about the spatial arrangement of atoms in the crystal lattice together with precise data concerning interatomic distances and bond angles. The three-dimensional information and the highly quantitative nature of the data distinguish X-ray crystallography from other analytical sciences such as microscopy or spectroscopy.
A proposal for celebrating the 100-year anniversary of X-ray crystallography since the discovery of X-ray diffraction was approved at General Assembly of the United Nations, and the year 2014 was assigned as International Year of Crystallography 2014 (IYCr2014). It is our great pleasure that X-ray crystallography has been used as one of the most important tools for materials characterization for more than 100 years.