Racemic compound of RNA duplexes, molecular model. The image shows a racemic compound of two double-stranded RNA. A racemic compound has equal amounts of left- and right-handed enantiomers. An enantiomer is one of two stereoisomers that are mirror images of each other that are non-superposable (not identical). Chain K (red) is D-enantiomer; it pairs with chain L (blue). Chain L (blue) is D-enantiomer; it pairs with chain K (red). Chain M (green) is L-enantiomer; it pairs with chain N (magenta). Chain N (magenta) is L-enantiomer; it pairs with chain M (green). D stands for dextrorotary (right-handed) rotation, L for laevorotary (left-handed rotation).