Erbium acetylacetonate
Erbium acetylacetonate is a coordination compound with the formula Er3. This anhydrous acetylacetonate complex is often discussed but unlikely to exist per se. The 8-coordinated dihydrate Er32 is a more plausible formula based on the behavior of other lanthanide acetylacetonates. The dihydrate has been characterized by X-ray crystallography.
Upon heating under vacuum, the dihydrate converts to the oxo-cluster. This behavior, which is also observed for other lanthanide acetylacetonates, further illustrates the implausibility of six-coordinate Er3.