Synthesis,structure, and magnetism of four polyoxomolybdate compounds containing yttrium and ytterbium

Four new polyoxometalate compounds consisting of Anderson-type anions and trivalent rare earth (RE) cations, [RE ₂ (H₂O)₁₄M(OH)₆Mo₆O₁₈][M(OH)₆Mo₆O₁₈]?·?14H₂O, RE?=?Y, M?=?Cr(1), Al(2); RE?=?Yb, M?=?Al(3), Cr(4), have been synthesized in aqueous solution and characterized by elemental analyses, infrared (IR) spectra, thermal gravimetric (TG) analyses, and single crystal X-ray diffraction. [M(OH)₆Mo₆O₁₈]^3? as a bidentate ligand coordinates to two RE ^{3 +} , forming a double-supported cation [RE ₂(H₂O)₁₄M(OH)₆Mo₆O₁₈]³⁺. The cations and other [M(OH)₆Mo₆O₁₈]^3? anions in the crystals are linked via hydrogen bonding interactions tightly, forming four supramolecular compounds. The magnetic properties of 1, 3, and 4 have been examined by measuring their magnetic susceptibilities from 2 to 300?K.