Comparison between diffraction-based methods to assign the absolute configuration of chiral APIs.

Technique	scXRD	PXRD Rietveld refinement	MicroED kinematical refinement	MicroED dynamical refinement
Sample requirement	– Large single crystal	– Crystalline powder with internal reference	– Crystalline powder with internal reference	– Crystalline powder
Advantage	– Reliability of results		– Reliability of results	– Minimal sample preparation
	– Straightforward data processing
Challenges	– Crystal growth	– Difficulty in solving complex structures	– Introduction of chiral reference	– Requires ED-specific data processing
		– Introduction of chiral reference