CCD diffractometer

X-ray single crystal analysis Data collection. Siemens SMART IK CCD. Diffractometer. Data collection by SMART (Siemens, 1995) cell refinement SMART data reduction SAINT (Siemens, 1995) program(s) used to solve structure SHELXS97 (Sheldrick, 1997) program(s) used to refine structure SHELXL97 (Sheldrick, 1997) molecular graphics XP in SHELXTL (Sheldrick,... 

Using three spherical crystals - the standard ylide crystal provided by Siemens Analytical Instrumentation, ruby and ammonium hydrogen tartrate (Enraf-Nonius standard crystal) - such an experiment has been carried out using two SMART CCD diffractometers. Before integration [8], all of the cell axes were multiplied by 2. Duplicate measurements were then averaged, and all odd reflections with values of F2 > 15 esd s were compared with the reflection with double the indices to obtain the best value of k for the expression F kl = kF h2k2). The average values of k obtained for the two diffractometers were 0.0014(2) and 0.00106(5). 

Figure 2.6 A modern CCD diffractometer. Note the circular area detector on the left, which acts as a very sensitive electronic, reusable equivalent of photographic film, allowing many data points to be collected simultaneously. (Photograph courtesy of Nonius.).

General for 2 and 3 Three dimensional intensity data collected on a Bruker SMART CCD diffractometer at 293(2) K MoK, radiation (0.71073 A) reflections corrected for Lorentz and polarisation effects and absorption corrections applied using SADABS structures solved by direct method and successive Fourier synthesis (SHELXS-97 and SHELXL-97) hydrogen atoms placed in calculated positions with fixed isotropic thermal parameters R = [(ZAF)/(ZF )] wR = Z[w(F "-F,2)2]/Z[w(F 2)2]i ... 

IG-21 was recrystallized from ethyl acetate to give colorless crystals (0.30 mm x 0.20 mm x 0.20 mm) suitable for X-ray single-crystal diffraction. The crystal structure of IG-21 was recorded on a Smart Apex CCD diffractometer using graphite monochromated MoKa radiation (A = 0.071073 nm). In the range of... 

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