enantiomeerne liig väljendab protsentides, mil määral on segus ühte enantiomeeri rohkem kui ratsemaati, For a mixture of (+)- and (−)-enantiomers, with composition given as he mole or weight fractions F(+) and F(−) (where F(+)+F(−)=1) the enantiomer excess is defined as |F(+)−F(−)| (and the percent enantiomer excess by 100 |F(+)−F(−)|)