Increasing completeness in single-crystal high-pressure diffraction experiments by pre-orienting crystals

Diamond anvil cells (DACs) exert high pressure while allowing light to access the sample. They enable single crystals to be investigated under extreme conditions by means of X - ray diffraction (XRD). Structure factors collected this way provide unique structural information, but their quality is never on par with routine experiments.1,2 A typical 35° opening angle of modern DACs renders up to 97% of the limiting sphere inaccessible. Resulting diffraction patterns are thus systematically incomplete, especially in samples with low internal symmetry, which impedes the crystal structure solution and affects the applicability of techniques that require high reciprocal space coverage.3,4