The symmetric and asymmetric molybdenum(V) dimers [4][PF6]2•DCM and 5 crystallize in the space groups C2/c and Pna21, respectively, with facial coordination of the ddpd ligands (Figure , Table , Table , Table ). The [Mo2O2(µ-O)2] 2+ motif is common for Mo V 2O4Ln complexes and the short Mo V -Mo V distances of ca. 2.5 Å are characteristic for Mo-Mo single bonds (Table , Table ). The molybdate(VI) [Hddpd]2 [6] crystallizes in the space group C2/c and the averaged Mo-O bond lengths in the cluster anion (Figure , Table , Table ) conform to previous literature reports. Overall, the results of our syntheses demonstrate that mer-1, mer-2 and cisfac- [3] 3+ are susceptible to oxidation and hydrolysis in solution, which has also been observed for other molybdenum(III) complexes in previous reports. In the solid state, the three complexes can be handled under air.