Electron density determination based on structure factors obtained through powder X-ray diffraction has so far been limited to high-symmetry inorganic solids. This limit is challenged by determining high-quality structure factors for crystalline urea using a bespoke vacuum diffractometer with imaging plates. This allows the collection of data of sufficient quality to model the electron density of a molecular system using the multipole method. The structure factors, refined parameters as well as chemical bonding features are compared with results from the high-quality synchrotron single-crystal study by Birkedalet al.[Acta Cryst.(2004), A60, 371–381] demonstrating that powder X-ray diffraction potentially provides a viable alternative for electron density determination in simple molecular crystals where high-quality single crystals are not available.

中文翻译：

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精确粉末 X 射线衍射得出尿素中的多极电子密度和原子位移参数

迄今为止，基于粉末 X 射线衍射获得的结构因子的电子密度测定仅限于高对称性无机固体。通过使用带有成像板的定制真空衍射仪确定结晶尿素的高质量结构因子，这一限制受到了挑战。这允许收集足够质量的数据，以使用多极方法对分子系统的电子密度进行建模。将结构因素、精细参数以及化学键合特征与 Birkedal 的高质量同步加速器单晶研究结果进行比较等人。[阿克塔水晶。（2004），A60，371–381]证明粉末 X 射线衍射可能为无法获得高质量单晶的简单分子晶体中的电子密度测定提供可行的替代方案。