Square prismatic geometry (D) is much less common compared to the square antiprism.  An example of a molecular species with square prismatic geometry (a slightly flattened cube) is octafluoroprotactinate(V), [PaF], as found in its sodium salt, NaPaF.  While local cubic 8-coordination is common in ionic lattices (e.g., Ca in CaF), and some 8-coordinate actinide complexes are approximately cubic, there are no reported examples of rigorously cubic 8-coordinate molecular species.  A number of other rare geometries for 8-coordination are also known.