A Simple Manipulative to Aid Student Understanding of the Spatial Orientation of d-Orbitals

Understanding Chemistry is very difficult for many first year university students. This is due in part to the abstract nature of the subject. One area students find particularly difficult to imagine is the spatial orientation of d-orbitals. This is critical to the understanding of the lifting of the degeneracy with approaching ligand fields, resulting in different geometries and the origin of color in transition metal species. The author describes a simple manipulative that allows students to construct mock d-orbitals in three dimensions. The mock d-orbitals may be added one at a time so students can construct a clear mental image of the spatial orientation of each orbital; singly at first and then as a group, around the nuclear center. The manipulative provides a way for students to go from the concrete to the abstract, and aids in understanding the splitting patterns of d-orbitals in different ligand fields.