These are far less common, and they can take up one of two different shapes. If you have six of them, this is the shape they will take up.

The two ligands attached to the ordinary arrows are above and below the plane of the rest. Those attached to a dotted arrow are behind the plane of the screen or paper. Note: Remember that the ligands attached to a wedge shaped arrow are coming out of the screen or paper towards you. The diagram shows four fairly random examples of octahedral ions. Four of the ligands are in one plane, with the fifth one above the plane, and the sixth one below the plane. In the simple cases we are talking about, that means that it will be attached to six ligands. These are complex ions in which the central metal ion is forming six bonds. You don't need to know about this to understand the rest of this page!

Note: If you are interested (although it is completely irrelevant to this page), you will find an explanation of how you work out the shapes of simple molecules and ions by following this link. The answer is just to learn the shapes you need to know about. Unfortunately that doesn't work for most complex metal ions involving transition metals. You will probably be familiar with working out the shapes of simple compounds using the electron pair repulsion theory. These shapes are for complex ions formed using monodentate ligands - ligands which only form one bond to the central metal ion. If you aren't sure what stereoisomerism is, you will find a helpful link further down the page. It goes on to look at some simple examples of stereoisomerism (geometric and optical) in complex ions. This page describes the shapes of some common complex metal ions.

Complex ion bonding