Bracketed Group Object

CDXML Name:bracketedgroup
CDX Constant Name:kCDXObj_BracketedGroup
CDX Constant Value:0x8017
Contained by objects:kCDXObj_Page, kCDXObj_BracketedGroup
First written/read in:ChemDraw 7.0 (written only)


Bracketed groups generally represent a collection of objects that is repeated some number of times, such as with polymers, mixtures, or other repeating units. Each contained object is listed by its ID in the kCDXProp_BracketedObjects property, and external connections are indicated by kCDXObj_BracketAttachment subobjects.

Bracketed groups may be nested, indicating that one set of brackets fully contains another set.

Each Bracketed Group may contain zero or more Bracket Attachments, indicating which bonds cross from the inside to the outside of the bracket. Although the cdx specification places no limits on the number of Bracket Attachments associated with each Bracketed Group, the presence of more than four Bracket Attachments can be ambiguous or unclear, and so it is recommended that four Bracket Attachments per Bracketed Group be considered a practical maximum.

As of ChemDraw 7.0, Bracketed Groups are written to files as they are saved, but they (and all contained properties and subobjects) are ignored when reading.

Although there are no required properties or objects, a Bracketed Group without any Bracketed Objects is pretty useless.

Value Name CDXML Name
0x8017 kCDXObj_BracketedGroup bracketedgroup
A collection of objects surrounded by brackets (or braces or parentheses).
0x8018 kCDXObj_BracketAttachment bracketattachment
A linkage that connects a Bracketed Group to some object outside that group.

Value Name CDXML Name Type
n/a n/a id UINT16
A unique identifier for an object, used when other objects refer to it.
0x0A24 kCDXProp_Bracket_Usage BracketUsage INT8
The syntactical chemical meaning of the bracket (SRU, mer, mon, xlink, etc). This is an enumerated property.
0x0A25 kCDXProp_Polymer_RepeatPattern PolymerRepeatPattern INT8
The head-to-tail connectivity of objects contained within the bracket. This is an enumerated property.
0x0A26 kCDXProp_Polymer_FlipType PolymerFlipType INT8
The flip state of objects contained within the bracket. This is an enumerated property.
0x0A27 kCDXProp_BracketedObjects BracketedObjectIDs CDXObjectIDArray
The set of objects contained in a BracketedGroup.
0x0A28 kCDXProp_Bracket_RepeatCount RepeatCount FLOAT64
The number of times a multiple-group BracketedGroup is repeated.
0x0A29 kCDXProp_Bracket_ComponentOrder ComponentOrder INT16
The component order associated with a BracketedGroup.
0x0A2A kCDXProp_Bracket_SRULabel SRULabel CDXString
The label associated with a BracketedGroup that represents an SRU.


CDX Documentation index