enantiomer excess (enantiomeric excess)

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 $e.e.$