Department of Chemistry, Liaoning University. Shenyang 110036, People's Republic of China Pyridine perrhenate acid; Pyrrolidine perrhenate acid; Crystal structure; CND0/2 The title compounds were synthesized and characterized by single crystal X-ray diffraction. C5H5N-HRe04 is monoclinic, belonging to the space group P2i, with a=0.5577(1)nm, b=1.2446(1)nm, c=0.5574(1)nm, [3=98.07(1)o. V-. 0.38307(1)nm3, Z=4, Rf=0.042 and Rw=0.046. Pyridine makes up for the tunnel packing with perrhenate, along the 2, axis of b direction. There is no inter or intra-molecular N-H hydrogen bond contact, but the H-O hydrogen bonds possibly exist intra-molecularly (H2-03, 0.2984 nm; H2-04. H3-03 0.2917nm;). C4H9N-HRe04 is monoclinic, belonging to the space group P2i/c, with a=0.5504(1) nm, b=0.8876(1)nm, c=1.6222(1)nm, p=96.14(1)o, V=0.78795(1)nm3, Z=4. Rf=0.076 and Rw=0.078. Pyrrolidine and perrhenate constitute a layer structure. There is an intermolecular N-H hydrogen bond contact(01. N1(1-x, y-1/2, 3/2-z). 0.2796nm; N1---03(1+x, 1/2-v. 1/2 + z), 0.2794 nm)and the H-O hydrogen bonds possibly exist intra-molecularly also (H3B-04. 0.2983 nm; H2B-04, 0.2952 nm). The charge distributions of these two compounds were calculated by CND0/2 method. The bonding energies of C4H9N-HRe04 and C5H5N-HRe04 are-7.033300 and-1.937900 a. u., respectively.