On a 2-D chart, returns an object that represents either a single column chart group or a collection of the column chart groups.
expression.ColumnGroups(Index)
expression Required. An expression that returns one of the objects in the Applies To list.
Index Optional Variant. The index number of the specified column chart group.
This example sets the space between column clusters in the 2-D column chart group to be 50 percent of the column width.
myChart.ColumnGroups(1).GapWidth = 50