Abstract: A new compound, H_{2 2} ·H₂O (bim= benzimidazole), was synthesized by benzimidazole, MoO₃ , et al. and characterized by IR spectrum and single-crystal X-ray diffraction. The compound crystallizes as a monoclinic system, having space group:P2(1)/n, unit cell with a=1.3882(14)nm, b=1.3927(14) nm, c =1.5940(16) nm,α= 90°,β=107.334(12)°, γ=90°, V=2.942(5) nm³, Z=2, R₁=0.0525. The compound has the ^4- cluster as the structural motif and covalently linked with benzimidazole molecules by Mo—N bond. The protonated benzimidazole cations and H⁺ cations play a role of charge-balance.