The imidazole coordinated novel heteropolyoxometalate Na_9[{Na (H_2O}_3{Co(C_3H_4N_2)}_3(BiW_9O_(33)_2]·33H_2O was synthesized by the reaction of Na_2WO_4·2H_2O with Bi(NO_3)_3 and Co(NO_3)_2 in pH = 7.5 aqueous solution. The single crystal X-ray diffraction study shows that the ciystal belongs to trigonal system, space group P3 , with a = 1.3904(4) nm, b = 1.3904(4) nm, c = 3.3169(13) nm, γ = 120°, V = 5. 553(3) nm~3, Z = 2, R_1 = 0.0361, wR_2 = 0.0507 (I>2σ). The structure of anion [{Na(H_2O)}_3{Co(C_3H_4N_2)}_3(BiW_9O_(33))_2]~(9-) reveals a sandwich-like arrangement of two {α-B-AsW_9} moieties enclosing three Co(C_3H_4N_2)~(2+) and three Na(H_2O)~+ . The coordination number of Co~(2+) and Na~+ in the sandwich anion are all five, and the polyanion has C_(3v) symmetry. Magnetic data have been fitted assuming that the only exchange-coupled centers are the cobalts, the compound exhibits ferromagnetic coupling with J = 6.90 cm~(-1), g = 2.10, and θ = 0.25 K.

Key words: HETEROPOLYACID, TUNGSTATE, CRYSTAL STRUCTURE, MAGNETISM, SANDWICH COMPOUNDS, GLYOXALINE P, SODIUM COMPOUNDS, COBALT COMPLEX, BISMUTH COMPLEX, COUPLING