Teaching Single Crystal X-ray Crystallography in the Undergraduate Classroom with Sugar and Epsom Salt

Abstract

We developed a single crystal X-ray crystallography experiment based on the crystal structure of sucrose (table sugar), and a more challenging experiment using Epsom salt. Both crystals are readily available in X-ray quality crystalline form. In these experiments, students mounted a crystal on a MiTeGen loop and analyzed it using a Rigaku XtaLAB Mini diffractometer (built 2011). Students generated models of both compounds using CrysAlis Pro , Olex2, SHELXT, and SHELXL. All aspects of this experiment use free software programs which have user-friendly interfaces. A step-bystep laboratory protocol for determining the structure of both compounds is included in the Supporting Information. These experiments were used in the Fall of 2019 at the Junior and the Senior level. In the Summer of 2020, a take-home version of the lab was created in response to the Novel 2019 Coronavirus (COVID-19) pandemic and implemented in the General Chemistry laboratory curriculum; this experiment was used for the duration of the 2020−2021 academic year. These experiments are suitable for all undergraduate experience levels.

Capturing the Precise Structure of Liquids: The Crystalline Sponge Method for an Undergraduate Laboratory Course

“…To address this challenge, we have tailored this technique to fit into two 4 h laboratory sessions and in a safer and more accessible way. An essential component of the crystalline sponge method, structure analysis, is considered challenging for undergraduate laboratory courses, primarily due to the need for a strong basis in physics and expertise. − To guide students through this process, we have developed a step-by-step laboratory tutorial for crystallographic analysis. Ultimately, we designed an integrated organic chemistry laboratory experiment for upper-division undergraduates, providing them a hands-on opportunity to learn about the crystalline sponge method for molecular structure determination of liquid organic compounds.…”