3-Carboxy-2-pyrazinehydroxamic acid was prepared by a one pot reaction starting from pyrazine-2,3-dicarboxylic anhydride with a high yield, and characterized by IR, Mass spectrum, 1H NMR and 13C NMR spectra and single-crystal X-ray diffraction. It crystallizes in triclinic, space group Pī with a=4.8659（10）, b=7.4233（15）, c=11.602（2）, α=96.904（2）, β=92.422（3）, γ=107.454（2）°, V=395.51（14）3 , Z=2, Dc=1.689g/cm3 , F（000）=208, μ（MoKα）=0.149 mm-1 , the final R=0.0473 and wR=0.1306 for 2853 observed reflections （I〉2σ （I））. A three-dimensional framework was assembled through intermolecular hydrogen bonding between water and 3-carboxy-2-pyrazine-carbohydroxamic acid molecules.
