it shows only crystals that appear in chiral or polar noncetrosymmetric space groups(SG). Determination of Flack parameters in general is possible only for crystals with compounds that contans atoms heaviest than Mg-Al(for lamda Mo radiation). The correct abs. config/ or polarity at Flack=0. for Flack=1 structure should be invertedor other SG shold be tested like P32 changed to P31. Sometimes flack parameter somewhere in benween 0 an 1, so it is recemic twin or non correct space group determination!(check high symmetry!)

Thank you! I ll check with high symmetry.

Got it. Thank you for your suggestions.

Using carefully measured intensity data, sometimes it is possible to determine the absolute configuration also with crystals having abundant O atoms.

See:

NEIDLE, S., ROGERS, D. Assignment of Absolute Configuration from Anomalous Dispersion by Oxygen Atoms. Nature 225, 376 (1970). https://doi.org/10.1038/225376a0

Thank you Gustavo Portalone Volker Kahlenberg Eduard Rusanov