Atom_Geometry Property

CDXML Name:Geometry
CDX Constant Name:kCDXProp_Atom_Geometry
CDX Constant Value:0x0430
Data Size:INT8
Property of objects:kCDXObj_Node
First written/read in:ChemDraw 4.5 / 6.0


The geometry of the bonds about this atom.

The number of bonds and implicit and explicit hydrogens must equal the number of attachments given in the table for the specified geometry.

Most of the values listed in the table below are provided for future expansion. The only value that ChemDraw reads or writes is Tetrahedral. For Tetrahedral geometry, the bonds attached to this node are listed in the kCDXProp_Atom_BondOrdering property in an order so that, when the node is viewed from the first-listed bond, the other bonds appear in a counter-clockwise orientation. This corresponds exactly to the '@@' chirality type in SMILES.

This property is used by ChemDraw only when reading files where no nodes have the kCDXProp_2DPosition.htm property. In such a case, ChemDraw will use the values in this property and in the kCDXProp_Atom_BondOrdering property to generate appropriate hashes and wedges on the attached bonds. If the generating program is saving positions, it is assumed that it will also be responsible for generating hashes and wedges.

This is an enumerated property. Acceptible values are shown in the following list:
Value CDXML Name Description
0 Unknown Unknown
1 1 1 ligand
2 Linear 2 ligands: linear
3 Bent 2 ligands: bent
4 TrigonalPlanar 3 ligands: trigonal planar
5 TrigonalPyramidal 3 ligands: trigonal pyramidal
6 SquarePlanar 4 ligands: square planar
7 Tetrahedral 4 ligands: tetrahedral
8 TrigonalBipyramidal 5 ligands: trigonal bipyramidal
9 SquarePyramidal 5 ligands: square pyramidal
10 5 5 ligands: unspecified
11 Octahedral 6 ligands: octahedral
12 6 6 ligands: unspecified
13 7 7 ligands: unspecified
14 8 8 ligands: unspecified
15 9 9 ligands: unspecified
16 10 10 ligands: unspecified

If this property is absent:

The geometry is treated as Unknown.


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