| CDXML Name: | AS |
| CDX Constant Name: | kCDXProp_Atom_CIPStereochemistry |
| CDX Constant Value: | 0x0437 |
| Data Size: | INT8 |
| Property of objects: | kCDXObj_Node |
| First written/read in: | ChemDraw 6.0 |
| Required? | No |
Description:
The node's absolute stereochemistry according to the Cahn-Ingold-Prelog system.
ChemDraw will preserve any value present in a file without confirming its accuracy -- as long as the structure is not edited in ChemDraw. Any change to a structure has the potential of changing its stereochemical descriptors, and so ChemDraw will recalculate the structure's chemistry after any change. As a practical matter, we are very confident about the accuracy of ChemDraw's calculation of stereochemical descriptors, so this behavior should rarely cause problems.
The Cahn-Ingold-Prelog system for describing absolute stereochemistry is defined in the following references:
This is an enumerated property. Acceptible values are shown in the following list:
| Value | CDXML Name | Description |
| 0 | U | Undetermined |
| 1 | N | Determined to be symmetric |
| 2 | R | Asymmetric: (R) |
| 3 | S | Asymmetric: (S) |
| 4 | r | Pseudoasymmetric: (r) |
| 5 | s | Pseudoasymmetric: (s) |
| 6 | u | Unspecified: The node is not symmetric (might be asymmetric or pseudoasymmetric), but lacks a hash/wedge so absolute configuration cannot be determined |
If this property is absent:
The node is treated as having Undetermined stereochemistry.
