Erythro and Threo 赤式&苏式 Terms used for diastereomers with two adjacent chiral C's,without symmetric ends. For symmetric molecules,use meso or d CH2CH3 CH2CH3 COOH COOH H Br Br H H OH H OH H Br H Br H OH HO H CH3 CH3 COOH COOH erythro threo meso (±)or(d,l) 2,3-dibromopentane tartaric acid =>Erythro and Threo 赤式 & 苏式 ◼Terms used for diastereomers with two adjacent chiral C’s, without symmetric ends. ◼For symmetric molecules, use meso or d,l. =>