Tripotassium tris(oxalato-kappa2O,O')aluminate bis(hydrogen peroxide) hydrate, the first example of a cyclic hydrogen-bonded H2O2 dimer.
In addition to associating into cyclic hydrogen-bonded dimers [O...O = 2.663 (1) and 2.914 (1) A], each hydrogen peroxide molecule in the title structure, K(3)[Al(C(2)O(4))(3)].1.75H(2)O(2).0.25H(2)O, hydrogen bonds to a neighbouring oxalate ligand [O...O = 2.700 (1) and 2.730 (1) A] and coordinates to two K(+) ions [K...O = 2.6620 (9)-2.8380 (7) A].