High-pressure X-ray diffraction studies of organic crystals

Abstract

Abstract The high-pressure laboratory X-ray diffraction technique is discussed in a view to its application to structural studies on molecular organic crystals. The signal-to-background ratio and accuracy of intensity measurements can be improved by using relatively big sample crystals and the smallest possible aperture in the gasket. Mechanical properties of the gasket material can be helpful in obtaining optimum experimental conditions when a big sample is mounted in the high-pressure chamber. The accuracy of measurements performed on organic crystals with a Merrill-Bassett cell and a CAD-4 diffractometer are illustrated with the results obtained in the study on the crystals of 1,3-cyclohexanedione at 0.52, 1.14 and 1.90(5) GPa—the structure which undergoes an interesting pressure-induced phase transition.