The structure of magnesium stearate trihydrate determined from a micrometre-sized single crystal using a microfocused synchrotron X-ray beam

Crystalline magnesium stearate has been extensively used as an additive in pharmaceutical and other industries for decades. However, the lack of suitably large crystals has hindered the determination of the crystal structure and thereby a more fundamental understanding of the structure-functionality relationship. Presented here is the structure of magnesium stearate trihydrate as determined from X-ray diffraction data of a micrometre-sized single crystal measured at a fourth-generation synchrotron facility. Despite the small size of the single crystals and the weak diffraction, it was possible to determine the positions of the non-hydrogen atoms reliably. Periodic dispersion-corrected density functional theory calculations were used to obtain the positions of the hydrogen atoms playing an important role in the overall organization of the structure via a hydrogen-bond network.

Automated summary

Crystalline magnesium stearate has been widely used as an additive in various industries for many years. However, the lack of large crystals has hindered the understanding of its crystal structure and the relationship between structure and functionality. This study determined the structure of magnesium stearate trihydrate using X-ray diffraction data from a micrometre-sized single crystal. Through advanced calculations, the positions of hydrogen atoms crucial to the structure's organization were also obtained.