Efficient single crystal X-ray diffraction data coverage using a kappa goniometer

This application note demonstrates the benefits of using a four-circle kappa goniometer for single crystal X-ray diffraction experiments.

Background

chlorothiazide
Crystal structure of chlorothiazide

The cornerstone of any data collection is having complete data upon which quality assessments can be made. Compared to other goniometer configurations, specifically those having fixed- and partial-chi configurations, the kappa geometry of the goniometer in the XtaLAB Synergy diffractometer series allows for more complete data collections to be conducted on those samples where measuring all unique reflections is critical. To test the ability of each goniometer configuration to measure complete data for both merged and unmerged reflections, the same crystal of chlorothiazide was measured on the XtaLAB Synergy-S restricted to both fixed- and partial-chi movements. Subsequently, the same crystal was also allowed to take advantage of the full kappa geometry of the Synergy. In just over one hour, merged data to IUCr resolution for chlorothiazide were measured to 100% completeness whilst unmerged data were collected to nearly 98% completeness. The kappa geometry of the XtaLAB Synergy allows for more complete data to be collected on those samples having P1 symmetry, especially when compared to those geometries of other goniometer configurations.

Geometry
 
Max completeness
merged (unmerged)

 
I/σ(I)
Fixed-chi   98.7 % (91.6 %)   45.2
Partial-chi 99.2 % (95.2 %) 46.0
Kappa 100.0 % (97.6 %) 48.3

Data Statistics for merged and unmerged data with different goniometer geometries

Request a PDF of the full application note entitled Efficient Data Coverage Using a Kappa Goniometer.