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Dictionary definition: absolute configuration
- Article from:
- A Dictionary of Chemistry
Copyright© A Dictionary of Chemistry 2004, originally published by Oxford University Press 2004. (Hide copyright information)
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absolute configuration
A way of denoting the absolute structure of an optical isomer (see
optical activity
). Two conventions are in use: The
D
–
L
convention relates the structure of the molecule to some reference molecule. In the case of sugars and similar compounds, the dextrorotatory form of glyceraldehyde (HOCH
2
CH(OH)CHO), 2,3-dihydroxypropanal) was used. The rule is as follows. Write the structure of this molecule down with the asymmetric carbon in the centre, the –CHO group at the top, the –OH on the right, the –CH
2
OH at the bottom, and the –H on the left. Now imagine that the central carbon atom is at the centre of a tetrahedron with the four groups ...