Tetra­kis(1,4-dimethyl­pyridinium) dodeca­molybdosilicate

The anion of the title compound, (C₇H₁₀N)₄[SiMo₁₂O₄₀], has a disordered centrosymmetric `pseudo-Keggin' structure and neighboring anions are linked into a layered structure via weak C—H...O hydrogen bonding involving the DMP cations.