Discussion on Preferred Orientation: from Metal-Organic Frameworks Synthesized by Different Methods to Pressed Plastic Crystals
JIA Xu1, REN Chong-Ting1, MI Jin-Xiao2, HUANG Xiao-Ying3, LUO Jiang-Shui1**
1. College of Material Science and Engineering, Sichuan University, Chengdu 610065, China;
2. College of Materials, Xiamen University, Xiamen 361005, China;
3. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China
Abstract Metal-organic frameworks (MOFs), due to their novel structures and extensive functions, are promising materials. Powder X-ray diffraction (PXRD) is a traditional material characterization tool which has been widely applied in university teaching and research. The experiments designed in this paper are expected to stimulate students' interests in the diffraction intensity equation (Hull/Debye-Scherrer Equation) of PXRD and the correlated Lorentz factor, in which we compare the inconsistencies between the experimental and calculated PXRD intensities of MOF-5 prepared by different methods. An attempt is made to delve into the reasons for the occurrence of this inconsistency in terms of the preferred orientation of the crystals and the three geometric factors that constitute the Lorentz factor. In addition, this paper constructs a new comprehensive university-level chemical experiment based on the principle of PXRD, the calculation results, the experimental results and the crystal nucleation & growth theory.
JIA Xu, REN Chong-Ting, MI Jin-Xiao, HUANG Xiao-Ying, LUO Jiang-Shui. Discussion on Preferred Orientation: from Metal-Organic Frameworks Synthesized by Different Methods to Pressed Plastic Crystals[J]. Chinese Journal of Chemical Education, 2022, 43(2): 69-76.
