Monopotassium monosodium hexahydrogen α-hexamolybdoplatinate(IV) undecahydrate

The title compound, KNa[H6PtMo6O24]center dot 11H(2)O, contains a discrete hexamolybdoplatinate(IV) [H6PtMo6O24](2-) polyanion (1 symmetry), which has the highest level of protonation. Five O atoms of the central PtO6 octahedron (mu(3)-atoms, Oc) and one O atom of an outer edge-sharing MoO6 octahedron (O bridging mu(2)-atom, Ob) are protonated. The polyanions are connected by almost linear O-H center dot center dot center dot O hydrogen bonds between protonated and unprotonated Ob atoms. Further consolidation of the crystal structure is accomplished by extensive O-H center dot center dot center dot O hydrogen bonding involving the uncoordinated water molecules. The two independent K+ cations are equally disordered about a twofold rotation axis.