Crystal Structure Refinement of Gaivinoxyl Radical, C29H41O2, Based on Synchrotron X‐ray Powder Diffraction and Rietveld Method

Abstract

AbstractHigh‐resolution X‐ray powder diffraction with synchrotron radiation coupled with Rietveld analysis has been used recently as one of the best way to obtain structural information from a powder specimen. Molecular and crystal structures of Che gaivinoxyl radical (C29H41O2) were studied by means of powder diffraction using NSLS (National Synchrotron Light Source) with λ = 1.5855 A and a rotating anode with Cu Kα radiation. The space group of the crystal is C 2/c with refined lattice parameters a = 23.786(1), b = 10.8611(4), c= 10.6766(4) Å, β = 106.634(3)° Z = 4. The peak shape was fitted with a pseudo‐Voigt profile function. The preferred orientation is along the >011< direction of the needle‐like crystals. Final refinements were converged to give agreement indices Rp 0.08 and 0.17 respectively for synchrotron radiation and rotating anode data. The fitting of the peak profile and refined parameters from the synchrotron radiation data are significantly better than those from rotating anode data. No significant differences are found between single crystal results and those in this work. This work provides evidence that powder diffraction, especially with synchrotron radiation, could be used as one means of structural analysis even for such a weakly scattering organic material.