Lacking all symmetry elements (other than the trivial one of a one-fold axis of symmetry), i.e. belonging to the symmetry point groupC 1. The term has been used loosely (and incorrectly) to describe the absence of a rotation–reflection axis (alternating axis) in a molecule, i.e. as meaning chiral, and this usage persists in the traditional terms asymmetric carbon atom, asymmetric synthesis, asymmetric induction, etc.
PAC, 1996, 68, 2193 (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2199
Blue Book, p. 480