Sub-Ångström Three-Dimensional Electron Diffraction Reveals Crystal Structures and Phase Transformations in Liquids.

Area of Science:

• Materials Science
• Crystallography
• Nanotechnology

Background:

• Understanding crystal dynamics in liquids is crucial for various scientific fields.
• Liquid-phase transmission electron microscopy (LP-TEM) offers potential for studying nanoscale materials in liquid environments.
• Atomic-scale crystallographic analysis of crystals in liquids has been a significant challenge.

Purpose of the Study:

• To establish a method for atomic-scale analysis of crystals in liquids.
• To capture phase transformations and determine crystal structures in situ.
• To overcome limitations of previous techniques in studying materials in liquid environments.

Main Methods:

• Development of sub-Ångström liquid-phase three-dimensional electron diffraction (LP-3D ED).
• Utilizing nanochannel liquid cells for confining ultrathin liquid layers.
• Employing liquid flow control for dynamic studies.

Main Results:

• Achieved 0.80 Å resolution 3D electron diffraction data from organic molecular crystals in liquids at room temperature.
• Observed the β-to-α phase transformation of glycine in situ.
• Identified in situ crystallization of a novel hydrated aluminum-glycine phase and determined its structure, including a hexanuclear aluminum-hydroxide-glycine cluster.

Conclusions:

• LP-3D ED enables atomic-scale determination of crystal structures and phase transformations directly in liquid environments.
• The technique provides unprecedented insights into structural evolution and solvated crystal structures.
• Demonstrated ab initio crystal structure determination at sub-Ångström resolution in liquids.