For a mixture of (+)- and (-)-enantiomers, with composition given as the 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(-)| ). Frequently this term is abbreviated as e.e. See optical purity.
