<P>There are five 3d orbitals called

3dxy

3dxz

3dyz

3dx2 - y2

3dz2

To make sense of it, we need to look at these in two groups:

3dxy, 3dxz and 3dyz

The names tell you that these orbitals lie in the x-y plane, the x-z plane and the y-z plane respectively.

Each orbital has four lobes. Notice that each of the lobes is pointing between two of the axes - not along them.

For example, the 3dxy orbital has lobes that point between the x and y axes. No LOBE actually points in the x or y direction. It is really IMPORTANT for what follows that you understand that.

Important: You will notice that the arrangement of the x, y and z axes isn't the NORMAL ONE. The x and y axes are drawn in the horizontal plane and the z axes drawn vertically. I don't really know why this is, except that it enables the curiously shaped 3dz2 orbital to be drawn vertically (see below).

3dx2 - y2 and 3dz2

Although these two orbitals look totally different, what they have in common is that their lobes point along the various axes. That's different from the first three where the lobes pointed in between the axes.

The 3dx2 - y2 orbital looks exactly like the first group - apart, of course, from the fact that the lobes are pointing along the x and y axes, not between them.

Be absolutely sure that you can see the difference between this orbital and the 3dxy orbital.

The 3dz2 looks like a p orbital wearing a collar! The main lobes point along the z axis.