Variation of structural motifs in lanthanoid hydroxo clusters by ligand modification

The isolation of multinuclear lanthanoid clusters with different nuclearities and geometries commenced as a serendipitous discovery and is now the focus of intense research, not only from a coordination chemistry point of view, but also in a variety of applied fields. This perspective analyses the structural library of reported lanthanoid hydroxo clusters to find trends linking their structural motifs with factors such as the specific lanthanoid, the bulkiness of the outer shell of ligands, the coordinating nature of the ligands, and the synthetic methodology. While trends are indeed starting to appear, does this signify that the synthetic chemistry of lanthanoid clusters has now progressed from serendipity to a more rational approach?