Topics

• While the electron-density studies are in most cases performed for a narrow range of temperatures about 100K, for substances at varied composition and occasionally for crystals at exited states, it is apparent that considerable changes of the electron density of molecules can be induced by pressure. For years structural transformations of substances at varied pressures were scarcely considered, and the scientists interested in the pressure studies faced considerable experimental problems. Only in 1959 the inception of the diamond-anvil cell allowed generation of very high pressures on one hand, and investigations of the crystal structures by diffraction and spectroscopic methods on the other. Since then the technique of high-pressure crystallography has been constantly developed.
  The influence of pressure on the properties of substances and on the structure of molecules and ions will be reviewed, and the state-of-the-art in the precise structural analysis at high pressure by diffraction techniques will be presented [1].
  
  [1] A. Katrusiak & P.F. McMillan (Eds.), High-Pressure Crystallography, Kluwer, Dordrecht, 2004.