Designations of stereoisomers of tris(didentate) metal complexes and other octahedral complexes.
See: helicity
Sources:
PAC, 1996, 68, 2193. 'Basic terminology of stereochemistry (IUPAC Recommendations 1996)' on page 2205 (https://doi.org/10.1351/pac199668122193)
Red Book, 3rd ed., p. 184 (https://doi.org/10.1515/pac-2014-0718)