With respect to the magnetic properties of f elements, actinide coordination compounds exhibit very different characteristics in comparison to their lanthanide analogs. This is due to the energetically comparable contributions of the relevant single-ion effects, namely the contributions of the interelectronic repulsion, the spin-orbit coupling and the ligand field. Therefore, the application of perturbation theory – well established to determine approximately the magnetic properties of (most) lanthanide centers – is not the adequate approach to unravel the magnetic nature of actinide centers.  We will start with a brief introduction to semi-empirical models including the aforementioned single-ion effects. Without applying perturbation theory, such models can precisely predict and reproduce magnetic susceptibility and magnetization data of isolated actinide centers, and can be readily extended for the consideration of actinide compounds with interacting centers.[1] By presenting selected examples, we will show intuitively surprising results that underline the differences between 4fN and 5fN centers as intrinsically anisotropic 5f7 centers, or the influence of covalent bonding on the energy splitting and composition of the wave functions of 4f3 and 5f3 systems as Nd3+ and U3+.