摘要：

Crystals are prepared and/or recrystallized [solvent] in one of the chemistry departments of our university. One crystal is selected [approximate size] and used on an Enraf-Nonius CAD4 single-crystal diffractometer, employing Cu Ker (X = 1.54184 ,&) or Mo Ka (~ = 0.71073 ,~) radiation with a graphite crystal monochromator. The unit-cell dimensions are determined from the angular settings of 25 reflections [0 range]. The intensity data [number of reflections] are measured, using the w-20 scan technique, with a scan angle of 1.5 ~ and a variable scan rate with a maximum scan time of 15 s per reflection. The intensity of the primary beam is checked throughout the data collection by monitoring three reference reflections every 30 min. The variation in the intensities over the course of the data collection [decrease in percentage if the crystal

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