Tri­potassium hexa­hydrogen­hexa­molybdo­cobaltate(III) potassium nitrate tetra­hydrate,K3[H6CoMo6O24]·KNO3·4H2O

The title double salt was obtained from the reaction of Y(NO₃)₃ and K₆H₄Co₂Mo₁₀O₃₈]·5H₂O at a pH of about 2.0. The H₆CoMo₆O₂₄]^3? anion is a typical B‐type Anderson‐structure heteropolyanion, and has an inversion center, with Co—O bond lengths in the range 1.907 (4)–1.919 (4) Å and Mo—O bond lengths in the ranges 1.709 (5)–1.721 (5), 1.902 (5)–1.951 (5) and 2.274 (4)–2.312 (4) Å.