Three new vanadate compounds of the formulas (C2N2H10)VO(OH)(4) (I), (NH4)(3)(C3N2H5)V4O10 (II), and V(OH)(3)center dot 0.97H(2)O (III) have been synthesized by a solvothermal method and characterized by IR spectroscopy, elemental analysis, and th ermog ravi metric analysis. The crystal structures of the above three vanadates have been established by single-crystal X-ray diffraction. Compound I crystallizes as tetragonal, space group P-4/mmm, with a = 9.0465(11) angstrom, c = 3.9897(10) angstrom, V = 326.51 (10) angstrom(3), and Z = 2. Compound II crystallizes as orthorhombic, space group Immm, with a = 3.6012(10) angstrom, b = 11.312(4) angstrom, c = 15.050(4) angstrom, V 613.1(3) angstrom(3), and Z = 2. Compound III crystallizes as cubic, space group Fd m, with a = 10.4252(17) angstrom, V 1133.1(3) angstrom(3), and Z = 16. Structural analyses reveal a one-dimensional beeline-chained structure, which consists of VO6 octahedra in I. Compound II possesses a two-dimensional V-O-layered structure formed by VO5 square pyramids; protonated imidazole and remaining NH4+ cations are inserted between the layers. The three-dimensional open framework of III with the pyrochlore type consists Of V-12 and V-4 secondary building units by using VO6 octahedra as building units.