The wiki: https://strucbio.biologie.uni-konstanz.de/ccp4wiki/index.php/Centric_and_acentric_reflections
says: "A reflection is centric if there is a reciprocal space symmetry operator which maps it onto itself (or rather its Friedel mate). . . . Centric reflections in space group P2 and P21 are thus those with 0,k,0." The operator -h,k,-l does NOT take 0,k,0 to its Friedel mate. it takes h,0,k to their Friedel mates. In other words the plane perpendicular to the 2-fold axis, at 0 along the axis Or am I missing something? eab ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
