On a 2-D chart, returns an object that represents either a single column chart group (a ChartGroup object) or a collection of the column chart groups (a ChartGroups collection).
expression.ColumnGroups(Index)
expression Required. An expression that returns a Chart object.
Index Optional Variant. Specifies the chart group.
Example
This example sets the space between column clusters in the 2-D column chart group to be 50 percent of the column width.
Charts(1).ColumnGroups(1).GapWidth = 50